I admit to being a bit of a pedant about apostrophes. Not saying that I get it right myself 100% of the time (I would cop to 99.8% though) but I keep seeing this particular gem cropping up more and more.
"Your" versus "you're". In this instance it's from a clip from the second season of "Project Runway Australia". The tricky old apostrophe of contraction. "Don't". "Can't". "It's". And in the old days, before falling largely out of use, "'phone" or "'bus" even.
Every time I see someone type "your stupid!" on a bulletin board I feel like asking "their stupid what?"