Oh, I just realized another one I can't believe I forgot-
I hate when people can't fucking figure out grammar.
General examples that people fuck up:
Their, There and They're
Your and You're
Its and It's
Oh, and people putting apostrophes on abbreviated or plural words.
In my opinion, if you can't get it figured out, you just look like an idiot.
Sorry Paul, you're my least favorite read.