Using Apostrophe's

One of my pet peeves is the misuse of apostrophes.  I find myself particularly annoyed by the misuse of you're and your, but any badness feels like teeth on tin foil to me. Not that I'm perfect, but...well...I'm sure some of you understand.  Anyway, courtesy of Blair Conrad, I found the following cartoon quite amusing.  Your mileage may vary

 

P.S.  The title was on purpose.