Why does Tom Sawyer avoid school? What doesn't he like about it?

Tom Sawyer dislikes pretty much everything about school
that has anything to do with learning.  He likes chasing after girls, and he likes
fighting with the boys.  But other than that, it is not much
fun.

He does not like to have to sit still in the school
room when it is nice outside.  He does not like having to listen to the teacher when he
could be playing with a bug on his slate.  He really does not like much of anything. 
Basically, Tom wants to be free, he wants to do things like going fishing and swimming. 
School prevents him from doing this.