Why make fun of, and put down Bush?

Why? What did he do that was so bad? For the war against terrorists, would you have let the people attack you over and over, and not do anything about it? And this housing crisis, it was caused by Fannie and Freddy, not Bush. Also, he had so much pressure on him, and could you have done any better? Just think, and what more could you ask of the guy? Also, what has Obama done that is so great?