If we're being honest with ourselves, the Hughes kids have not exactly been known for their humble, down to Earth attitudes. They've always been cocky jock types. Sounds like Luke takes after his brothers. Not a shocker. He'll grow up with time.
It would have to be something especially bad for this to be remarkable. I feel like it goes unsaid, but a lot of these kids are not the most pleasant to start with. They're immature, cocky, and think they're surefire millionaires in the making. They get better with time and adversity. Luke probably will too.