I told him this.

"There's nothing wrong with being idealistic. In fact the world needs people like you. But there's one thing to watch out for when you're an idealistic person. 

"People will try to beat you down. 

"Because everyone was idealistic once. Everyone wanted to do some good for others once. But things changed, they grew selfish, and now only want good things for themselves.

"When they see people like you, they cannot stand it. They will want to make you become them. If you become them, it will prove to themselves that no one can remain kind, and good, and idealistic, in this cruel world. Therefore it was not their fault that they became selfish, self-serving, and mean. No one could do otherwise.

By you remaining yourself, it shows them just how small and disgusting they are. They cannot stand it. They will want to take you down. Do you understand what I mean?" 

And he nodded his head.