It irritates the shit out of me when people think they're using proper grammar, but they are actually incorrect.
e.g. - someone tags a photo with "My baby and I"
Also, pretentious assbags that think they fully understand the application of good and well. When I ask someone "How are you?" and they reply, "I'm well. How are you?" and I say, "I'm good." They look at me like I just showed them a shit covered tampon. No motherfucker, I asked how you are. In this case, good is a state, Well is an adverb or only applied when asked specifically regarding your health. I don't take the time to correct you because I'm not a high-nosed, small-dicked little shit. You, however, are. Point your condescending dick receptacle elsewhere.
Sorry for the rant.