What is are 1 or 2 strange pet peeves you have?

When people say ''your'' when the sentence calls for ''you're'' or when people say ''that don't work'' <-- example. OMG i'm such a grammar nazi. I hate when people do that, it drives me insane. Or when people say **** like ''dis'' instead of ''this'' or ''dat'' just, AH! It annoys me.