The ones I hate are
Van GO
N rowt
Noter Daym.
How is the first one supposed to be pronounced?
As for the third, in America, there is a rather famous University called "Notre Dame" and it's pronounced "Noter Daym", so there's that problem.
As for the last, what I find irritating is when people try to put in the linguistic inflection. It happens a lot with Spanish words; someone will be speaking in perfect diction English, and they'll throw in a Spanish word and all of a sudden it sounds like Keenan Thompson imitating David Ortiz on Saturday Night Live.
Me? I actually mispronounce a ton of words, because I got most of my vocabulary by reading, and so I had to sort of formulate (read: GUESS) the pronunciation myself, and so I know a ton of words that I've never actually heard pronounced at all, let alone pronounced correctly.