The uncreative memes are the least for me, though. What I'm really happy to see being left behind are:\
"I don't understand" to convey "I disagree, but if I feign stupidity I'm going to tire you down while making you look angry and irrational for not spoonfeeding me basic reasoning"
the "lol", "lmao", and emoji spam. I don't mind the acronyms themselves, but it's really hard to talk about anything serious with redditors
"As a" [insert label]. It does pop up here sometimes, but in Reddit it's everywhere. It's like they believe that something becomes "magically" truer/falser because you claim that you're some random label.
Bots that "join" conversation to boss you around. Here there's the piped bot offering alternative links to botnet videos, but it does a service, unlike those fuckers. (I'm looking at you, common misspelling bot. The fact that someone spelled "wierd" for "weird" is irrelevant. Stop. Adding. Noise. You. Fucking. Waste. Of. Electricity.)
The mods. Yes, there are good mods there... and they don't usually last long. Shitheads though are a dime a dozen, because they followed the admins' "how to treat users" pamphlet to the letter.