show-off

(noun) a person who displays his or her achievements or good characteristics to make others feel bad

Example Sentence:

A: Do you like your new roommate?
B: No! He has a beautiful girlfriend, a nice car, good looking friends and really nice stereo system. He brought them all over last night to see his new place.
A: Wow, your roommate is a show off!

The young skateboarder enjoyed being a show off because it made all of his friends jealous of his skateboarding abilities.