o.o I thought this thread was going to be about the Weird Al song. Heh.

That said, I can't think of any particular word misuse that grinds my gears. Bad grammar in general tends to be enough of an annoyance. 

Oh, except for [url=https://www.youtube.com/watch?v=NARxgXEdlzs]this common mistake[/url]. 

Yeah, that's kind of embarrassing. :hehe