Misanthropy
I probably first swayed towards misanthropy due to teachers telling me off for what I considered to be arbitrary reasons - simple misunderstandings, correcting me though I was correct, the like. Maybe I was in the wrong often, but it still made me less trustworthy of people.
It's much easier to be misanthropic if you read the news, too - the countless wars and corruption, which can make you look at humans in general in a more negative light. Perhaps social media has amplified this, maybe not, but considering words like "doomscrolling" are now more popular, I think it has.
I went cycling recently and had an ironic encounter with a group of people, perhaps younger than me. They heckled me for cycling, possibly due to how I looked, which I found curious. They were waiting at a bus stop, perhaps for a while, and were goading me for being more physically active at the time. Who knows, maybe they're always active, but I still found this quite unusual and funny. I ignored them because I had no time for them.
It's similar with younger people who like mocking you for no reason. They're the kinds that mess around because they think they're funny, not realising they're a fucking joke. They'll mature in due time, hopefully soon.
And because of this, I find myself thinking more often than not that humans aren't great. I know that's a mistake, many are very good and I have many friends who go against that argument. Yet it's sometimes hard to ignore the vocal minority that ruin your day.