And there is a certain neuroticism that leads some people to review your post history before making a snarky comment. I have noticed that, but it's not the norm.

Yes sometimes it's sneaky, some aren't even hiding they stalked you before engaging a conversation.

I sometimes look up peoples history before replying.

It tells me if I should reply carefully and nicely because someone is just having a bad day or don't know the language - or if I should just drop the reply and flag instead.

You havent touched anonymous boards? Compared to Imageboards (4-chan,etc), textboards are more calm and slow.