If one day we are to vote for the best post on the forums ever, Adrian's post would take my post. I can't remember the amount of times I tried to teach some the different between his and he's. I am only sorry for not mentioning another mistake that is pretty common around these parts, removing the space between a and lot to make a horrible word.
True, and your English is tip-top, but the problem I have is that I'm American, half of my countrymen can barely speak English. I feel a bit hypocritical telling a kid from Azerbaijan that his "your" and "you're" is off when he probably speaks at least two languages other than English.
That is one of the problems with America, we need to teach our children to speak English first, well at that, then Spanish and French....
But why expect that when our kids think Tbilisi, Georgia is next to South Carolina.