Not only the obvious “AITA for leaving my mafia boss husband after he murdered my family” deleted AmITheAngel crossposted posts that everybody knows it’s fake, but also, some viral post that everybody believed to be true and they never called it out or realized it too late after some ridiculous update.
I’ve seen entire comment sections replicated by bots. Word for word, comment for comment. Was a massive wake up call.
The most fake comments I’ve seen were many GPT bots in /r/programming, always making top-level comments responding to only the title.