I have felt the same at one point or the other but the truth is that he sees something in you that you don't see. He does not need to like you for your looks, how athletic you are, or if you are talented. He likes you because of your personality.
A guy was dating a very pretty girl and then they just broke up. Now supposedly he has a crush on me yet I don't feel special or pretty. She's athletic, fast, liked by many while I'm the opposite. Why do you think he would do that?