Hope

I hate english and writing papers and all of that kinda stuff, but when it comes to grammar and puncuation it bugs me when things are wrong. On our trip to California a couple of weeks ago we stopped in Hope, AZ and took the following picture.

Can you tell me what's wrong with it?? Here's a clue:

"Y-O-U-'-R-E means you are, Y-O-U-R means your!"

Can you name who said that quote, what they were talking about and what it's from?? If you know me at all, it should be pretty easy to guess what it's from.