Arrogance

Telesa • I wish I had a real dragon...
There's the kid I used to go to school with, and he was really nice, but when we hit middle school and he started playing football he turned into a complete jerk.
Now I go to a different school and in our football league was my old school. We crushed them in a 41-0 slaughter. But this guy's dad is like "oh it's just because they didn't play my son" "my son is the best football player" "No one is better than my son" 
I just want to punch both the son(s) and the father because I hear about is how "great" and "perfect" this guy is; but the kid is the total worst! He does so much crap behind his dad's back its not funny! I wouldn't be surprised if he was doing drugs.
What's your opinion? Is there a point where "praising" your child has to stop? Or is it alright to puff them up and make them think they are better than everyone else- when they're really not?