I think my pet peeve would be, ummm, ooh, I know.
I think my pet peeve would be when my cat keeps on "watching" TV even after I've turned it off. My cat loves to watch TV when we have it on and sometimes she'll just sit there staring at the blank TV screen (she sits like an inch away from the screen. LOL) and sometimes it annoys me for whatever reason, so I move her some place else (more often than not she goes back to her original spot in front of the TV).
Anyway, I think that would be one of my pet peeves (I can't think of any others right now. LOL).