My list is so long ... I'll stick with the most annoying.
Certain of my family members used to talk like this: "OMG, that dress is just, like, so gay! How can you think it's cute? You are so retarded! Ew!" I can't STAND "text message speak" being used out loud; I can't STAND "gay" and "retarded" being misused (how is an article of clothing gay???); I can't STAND "like" being used constantly for no particular reason.
Now, as I get progressively sleepier/angrier/more intoxicated, my own speech tends to degenerate into a very Southern slangy mess that I'm sure would bug everyone on this board