YSK it's either "should have" or "should've". "Should of" is incorrect
Why YSK?
The first person who typed "should of" probably heard of it in real life that was meant to be "should've", they typed "should of" online and readers thought that it's grammatically correct to say "should of" which is in fact wrong and it became widespread throughout the years on Reddit.
I know right, I know people make careless grammatical mistakes all the time, including me, which is completely fine but people outright thought that "should of" is correct and use it all the time starts to get annoying
It's mandatory in a series, only. Something is only a series of there are three. Plenty of time the cadence and diction sounds like a series but isn't.
If the first two or last two are antecedent to one another, you don't need the comma. Said another way, if the first or last noun is not severed from the second, you need a serial command to indicate that.
Oh, Dude! I'm 99% for it. On the night before my uncle's funeral, while labeling photos for the slideshow, two of my cousins got into an Oxford comma fight.
John, Joe, and Jeff.
Take out the second comma.
But it's right!
But it looks stupid!
Fight! Fight! Fight!
I reflected on the the whole thing after hearing opinions from both sides of users. I now realise I don’t care as much anymore which may be a good thing.
Also, pleeeaaase, someone find me that ancient image macro of a boy, maybe he had a moustache, or maybe it was drawn on, he was raising an eyebrow, and the only caption on it was "que?". I've been searching for that forever.
should of is probably a product of phonetic typing (those who just type the letters that match the internal audio) or when siri first launched voice typing and no one bothered to check it.
Edit: Should of should've died a long time ago tbh. could do with a mini-crusade.
"Should've" and "should of" are pronounced the same, what are you talking about? There's no way you can mix them up in speech. Are you even a native English speaker?
While it is true that "should of" etc. can easily originate from a confusion between "'ve'" and unstressed "of", which sound identical, the statement
"Should of" is incorrect
itself is at least a bit misleading and prescriptivist in its generality.
Interestingly, there seem to be at least some native English speakers who genuinely do say "should of" (with a stressed "of") sometimes. This paper for example argues that people who say "should of" really do use a grammatical construction of the form modal verb + of + past participle. One argument the author mentions is that this would also explain the words "woulda", "coulda" and "shoulda", since "of"->"a" is quite common in general (e.g. "kind of" -> "kinda"), but "'ve"->"a" basically doesn't occur elsewhere (e.g. no one says "I'a" or "you'a" instead of "I've" or "you've"). Another is that the reverse mistake, i.e. using "'ve'" in place of "of" (e.g. "kind've"), is much rarer, which is a clear difference to e.g. the situation with "they're"/"their"/"there", where people use these words in place of the others in all combinations frequently. I recommend this blog article for a much longer discussion.
Also, whether genuine mistake (which it almost certainly is in many cases, although probably not all) or different grammatical construction, YSK that "should of" etc. didn't just become popular recently, but have been used for centuries. E.g. John Keats wrote in a letter in 1814: "Had I known of your illness I should not of written in such fiery phrase in my first Letter.". Many more examples (some older as well) can be found e.g. here or here.
TL;DR: While in many cases "should of" etc. can well be a mistake, originating from the fact that it sounds identical to "should've" when unstressed, there is some interesting linguistic evidence that at least in some dialects of English native speakers really do say "should of" etc. (i.e. in those cases it is not a mistake, merely non-standard/dialectal).
...the reason "in some dialects of English native speakers really do say 'should of' etc" is phonetics. Kids hear "should've" and repeat it phonetically, before learning the actual words or their meaning. Combine that with the awful state of education and literacy in the USA (and other countries etc) and voila, you've got some armchair internet expert justifying it with some big words trying a weeeee bit too hard to make it work.
Then you've got teachers who still gaf and know their shit who will correct this before middle/high school, and no, last I checked it was never added to the dictionary or considered correct. Language of course is living and ever changing, but the line must be drawn somewhere lest we devolve into shouting and grunts like neanderthals
A common mistake is to write ‘could of’ instead of could have or could've
I could of told you that.
I could've told you that.
The reason for the mistake is that the pronunciation of ’ve is the same as that of of when it is not stressed. This is a common error but it is definitely considered wrong in standard English.
"Should of" is grammatically incorrect, regardless of whether the user/speaker is aware of its incorrectness. It's a fact, and a fact per se cannot be misleading. It's as simple as that. Linguistic conventions, as you've illustrated, can be formed over time, but that again doesn't take away from the fact that such usage is grammatically incorrect to begin with.
Just read the second (or the first, but that is more technical) link I shared. Some native speakers do in fact seem to say "should of" even when the "of" is stressed, so in their dialect it would be grammatical.
Not wanting to be purposefully controversial, but language is a tool for communication and as long as it's understood by the target audience, then I'd say it was used effectively.
The English language doesn't have a governing body (unlike say French and Spanish) and so whatever we agree on is correct usage. "Grammatically incorrect" has long been a dog-whistle signifier for elitism (you don't have the expensive education to know what's correct) and racism (the local dialect that you speak isn't our 'prestige' version, therefore you are inferior) and I don't really like to see it. Even when those aren't your intentions when correcting people, it still rankles with me.
Not that I'd write 'should of' on my CV or anything, but it doesn't offend me any on an internet forum.
and as long as it's understood by the target audience
Duy'ou-ndarstend Diz?
Understanding written text is more difficult when the existing established conventions that impart meaning are ignored.
Sure, those conventions evolve over time, some errors are worse than others, and no one's going to write perfectly all the time. But that doesn't mean anything goes and the writer has no responsibility to write clearly and correctly.
True. Just because "language is descriptive" (descriptivist will always let you know) doesn't mean everyone can go freestyle with language, carelessly introducing ambiguity and miscommunication. They always say "as long as it gets the point across" but as a non-native but still pretty fluent, most of the time they don't actually get the point across.
What I'm hearing is we need to set up some kind of formal governing body to properly enforce the grammar rules of English. Maybe Hugo boss could make some uniforms.