I delete about 80% of the comments I write before posting. Even if I took the time to write a long response. This is because of the general nature of the Internet and reddit culture is definitely here on Lemmy. But, like this comment, I'll try to engage more because I also miss the discussion aspect on posts.
Most people are guilty of that to some extent. You want to make a good response, but end up overthinking it and moving on. Which is a shame. God only knows how many awesome comments end up in the digital wastebasket.
Besides, what’s the worst that can happen? Who really gives a fuck about downvotes anyway.
I do the exact same thing, once my comment reaches a paragraph long I just think "this is way too much stupid information to add, fuck it all, cancel." Maybe I should shitpost random thoughts either way and let the chips fall where they may.
I often realise as I've written it that I may be doxxing myself (sharing an anecdote about my past etc) so often that's my reason to delete. It's pretty paranoid but I do value my anonymity here.