Oh man, the your/you're thing really gets on my nerves when people don't use the correct form. It doesn't even look right, I don't know how they could actually think that's the right way to say it. You're = You are, you can tell by the letters! Oh well, I usually don't correct people on it because then I'll come off as a jerk, but I can't help laughing when someone spells it wrong, especially if it's in an essay.