While the life of a celebrity may look easy, the path to get there certainly is not. Most of the superstars who have dominated popular music had to work hard to get on top. And most of them had to wade through a pile of rejections to get there. Hindsight, they say, is 20/20. To whom do we refer when we say "they," though? We're mostly talking about the people who passed up the chance to sign these superstars.

The lesson to be learned here is not for record executives. It's for aspiring artists. If you love doing something, keep doing it. And keep pestering the crap out of everyone you can think of until somebody gives you a chance. If your intention is to be as big as Madonna and U2, you're gonna have to be a little aggressive. And you're probably going to need thick skin. Like they say, everybody's a critic. So to give you some inspiration, here are five of the most surprising rejection letters of all time: