Why...

A little boy asked his father, “Why does comfort make you feel good but also lazier than before? Why does pain make you feel terrible but also stronger than earlier?"

His dad replied, “Go ask your mother. Just the other day she questioned why one fish is blue and another silver?"

“What did you tell her?" asked the little boy.

“I told her to go ask her mother."

“You lead a dangerous life," said the little boy.

“But I'll live," replied his father.