Are you optimistic or pessimistic about the future of the world?

Both. I do believe that "communism will win" as an inevitability (with one big caveat, see below). Capitalism obviously is unsustainable and rife with internal contradictions that can only lead to its eventual demise. The obvious and broad example being that it requires infinite growth on a finite planet. But I think it can get very bad before it gets better, and expect it will further devolve into fascism (much more so than it already has) for most if not all of the western world, and the entire world will suffer as a result. Socialism, then communism will eventually emerge (since fascism is just as doomed by its contradictions as capitalism is), but before we get there, I expect there is going to be some truly unimaginably dark and horrible times on the way there. So in that sense, I am ultimately optimistic about the future of the world, but extremely pessimistic about its more immediate future.
But now for the caveat. I think that most people, even leftists, don't fully appreciate how much climate change is going to reshape the world. There is a real chance that it will get bad enough that civilization may not survive, that humanity as a species will be among the many that don't make it through the mass extinction we've only just entered. Even people fully on board with knowing climate change is bad and must be curtailed as much as possible as soon as possible still mostly don't realize how much a genuine existential threat it is on a planetary scale, on a scale of centuries and longer. It is by no means a certainty, but given the feedback loops we don't fully understand and definitely don't know how to interrupt, there is a possibility of Earth even going the way of Venus. Obviously I hope that's not the case, but it would be a mistake not to recognize the extreme potential of climate change. If we are able to mitigate it in time, I am like I said, ultimately optimistic. But I am beyond afraid that we won't be able to mitigate it in time.
In other words, it's not just "socialism or barbarism," it's socialism or annihilation.
- Well...
  Earth becoming more like Venus is an inevitability in the high hundreds of millions of years (and for scale, multicellular life has been around for roughly 5-600M years, with the more than 3 billion before that just being simple single-celled prokaryotic life), but that is completely independent of anthropogenic climate change, it is because of the expansion of the sun towards it's red giant phase. In terms of being habitable to life, Earth is easily past the half-way mark already, no matter what. However, that is far enough out that it doesn't bear worrying about and isn't something we can have any sort of impact on.
  That said, the climate change that we as a species are causing right now could lead to a runaway greenhouse effect on much shorter time scales. The fact is, there have been times in Earth's history where it has been so hot that complex life could mostly only survive at the poles (with the equator being a death zone to all but simple, single-cellular extremophiles) and there have been times where Earth was encased almost entirely in ice except perhaps at the equators - not just our usual conception of an ice age, but "snowball earth," and this was likely caused by certain forms of simple life, fascinatingly enough. The feedback loops we are triggering right now have a potential to drastically change the composition of the atmosphere on a far shorter timescale, one in which we are talking about an end to most complex life (obviously ourselves included). It was almost certainly volcanism that caused Venus to go from a mostly habitable planet to the completely, utterly inhospitable world it is. Volcanism has also been responsible for extreme heat and mass extinctions on Earth, but obviously it never tipped over into Venus-like territory. The thing is, right now we're changing the atmosphere at a rate far faster than volcanism has in the past! And rate of change matters a lot with this kind of thing. I'm repeating myself, but again, it is not a certainty but it is a possibility that anthropogenic climate change could hit tipping points that Venus-ifies Earth on a much shorter, nearer term than anything relating to the expansion of the sun, on time scales that are worth worrying about (if we value humanity as a whole), and is the sort of thing we can have an impact on.
- Unscientific take on climate change, IMO
  What I've read from scientists/experts doesn't paint that picture at all.
  Catastrophic weather events will kill millions, but not a billion.
  
  Then you need to do more reading because I did work in this field and have read the science on it as well. First all, you have to take into account what time scales are being discussed. What you're reading is, I'm all but certain, just talking about the coming few decades, in which yes, millions at least will likely die. And even then the science that tends to reach the public is toned down, pacified, and doesn't represent the whole truth. You should be familiar with this as a communist trying to get an understanding of what's really going on with the world via popular journalism. Is what you're reading about "catastrophic weather events" also discussing what will be happening 1000 years from now? 10,000? Despite the longer scale, what we are doing right now and in the coming decades will have an effect on those longer scales. Climate change is so much more than simply an intensification of weather events. It is literally a rapid change to the composition of our atmosphere. An atmosphere which has, by the way, been completely altered by life in one of the most chemically fundamental ways possible, from a reducing atmosphere to an oxidizing one. This is what I mean when I say even many leftists just do not understand how extreme the risks are here. A runaway greenhouse wouldn't just kill a billion, it could well end our species and most other species of "higher lifeforms."

My internal legal counsel has advised me not to discuss the topic with myself

Technology used to be a thing to be optimistic about. The past 10-15 years or so has been a bit of a let down with capitalism fucking everything up.

Very pessimistic. Besides the current problems like wars and Trump becoming the next president of the USA (which as a European citizen really scares me), climate change is going to fuck over human scociety big time in my life time. Well, it already is but still humanity as a whole is doing jack shit about it. Giant oil companies keep digging for new oil and gas, the best selling cars are unnecessarily huge SUV's, planes are still being subsidized rather than trains, humanity keeps eating meat, plastic usage and production is barely going down.
The current problems the news is full about don't really matter in the long run when we're literally making our planet unliveable and humanity is clearly still denying it.
- According to the GIEC (IPCC) report if nothing changes, and nothing is changing as you remarkably said, the fall of our society will start in 2040 because of food shortages due to the climate.
  2000 fucking 40! It’s tomorrow. I am destroyed by this future and really don’t understand corporate and/or politicians.
  I still have friends making babies and not think that their life will be miserable in less than 20 years.
  
  I feel you. I want children but agreed with myself long ago that they will be adopted because I don't want to bring children onto this dying planet.
  My country (the Netherlands) is going to be majorly flooded within the next 100 years (but probably sooner) but the majority of buildings built to stop the housing crisis are still build under sea level in the major cities.
  People think they're not climate change deniers but 95% of them most definitely are.
  
  Is this it? https://www.ipcc.ch/srccl/chapter/chapter-5/
- There was four years of Trump and nothing particularly bad happened.
  In fact, global instability has been markedly worse in the four years since.
  which president's administration directly attacked Europe with the Nord Stream II bombing?
  
  There was four years of Trump and nothing particularly bad happened.
  Except that time a million and a half people died and literally the whole country had to stay inside collecting unemployment and washing our groceries while all of his followers got super amped up and violent because they weren’t (always) being allowed to make things worse
  And that little bonus surprise at the end and how a sizable portion of the country including some important judges hates elections and anyone who makes them happen now
  I mean there’s more but those are good starters
  
  Under Trump America withdrew from the Iran nuclear deal. I'd say that move did negatively affect today's global stability.
  
  There was four years of Trump and nothing particularly bad happened.
  He didn't really have a plan for his first term. That's why he only was able to do a few bad things. This time around there is a plan.
  
  actually, it would seem that the nordstream attack was a bipartisan effort, with the plan already having gotten support under Trump:
  https://www.youtube.com/watch?v=xrFdHO7FH8w&t=1260
  interviewer: what's your relation like with vladimir putin? donald trump: i think it's very good, but i was tough with him. i ended the pipeline. it was called nordstream 2.

Realistic. The world will be fine, not so much for most of the lifeforms that currently populate it. Earth has gone through evolutionary resets before. The existence of deep sea hydrothermal vents with methane loving organisms means that Earth will most likely NOT become like Venus, even when all feedback loops run their course. The carbon released and washed into the oceans will feed the species that produce oxygen, just as it has before.
Humans have become their own asteroid.

I see the near future/current world as basically RoboCop but more gore and less funny. and also without RoboCop.
- Instead of RoboCop we're gonna get those robot killer dogs from Black Mirror

I think that the first 20 to 30 years will be very difficult for humanity. There is a distinct reactionionary movement that is blocking or even reversing progress needed to fix various problems (including, but not limited to climate change, destruction of ecosystems, housing problems and the world population aging beyond sustainablitiy). It will get very messy.
After the boomer generation has died out as well as my own (GenX-er here), humanity can hopefully look forward again. As I age, I really think that it is our two generations that are blocking progress. As millennials and Gen Z ages, they will hopefully learn from us how not to do things.
- I just don't see how. They are equally indoctrinated into the societal constructs that are creating the problems. The "boomers" were equally and imperfectly against the negative operating principles of their society when they were younger. They got played. Now we are faced with even more powerful special interest group (the ultra rich), with even less checks and balances than during the past 80 years. And now we're getting played too

I assume you mean in the long term, like looking centuries or more out. If the scope is different my answer might be different.
It's a total unknown to me. The biggest question is where the Enlightenment came from after millennia of producing the same system over and over again, and if it's here to stay. MAD and GAI are the other two big existential threats. Other problems can all be recovered from in the long arc of history. (Yes, even climate change)

Pretty pessimistic, short term (the next decade or two.)
I am optimistic about socialism and anarchism very long term (the next 100-1000 years,) maybe just because I try to remain hopeful on stuff like this.
Humanity has created some incredible things, we have so much potential to be a boon for the planet, for the animals, and for each other. But we must oust Capitalism, corporatism, statism, and fascism to even have a chance.

Pessimistic/realistic. There's lots of pollution, most food is low quality because it's cheaper to manufacture and aiming for looks rather than increasing quality raises profits. Technology is specifically made to be hard to repair and has set lifespan plus all the licensing and subscriptions. No privacy. Everything moving to cloud for even more control. Corporations have way too much power and can get away with almost anything. Supermarkets can be more and more expensive without signing up for their loyalty programs. Education is stuck in the past. ...

middle

Extremely pessimistic to the point that I have a planned out when the dumpster fire gets close enough to ruin what little peace I have.

Optimistic, because, why not?
- Because capitalism.

Pessimism of the intellect, optimism of the will, etc

Optimistic. I am going to singlehandedly will the future I want into existence

Nuclear annihilation is the least painful route we can take.

Is this some sort of trick question

Optimistic. Even if we all die, consciousness can evolve again. Even if we end up tortured for all eternity by robots, after a few million years we’ll be godlike and able to transcend that reality. Those who would be able to create it recognize this fact, and so there’s a mechanism by which the most intelligent are most aware of the inescapability of karma.
Given the perfection of the information ecosystem in its most abstract form, I predict increased pleasure and joy and decreased betrayal and suffering as time goes on.
Might be right in the near term, but everything will be okay.
- Even if we all die, consciousness can evolve again.
  Yay! Time to re-evolve and make all the same mistakes again! Infinite suffering, forever!

Pessimistic.
The more times I see people not fighting for the rights and benefits that they deserve, the more I am shying away in disappointment. We continually allow defeatism to cloud us to where it's no wonder why governments, corporations and other filth have such a field day with us.
I'm just waiting for something, anything, to put all of us out of our misery.