Who said "Why so serious? Let's put a smile on that face."?

This quote is attributed to The Joker.

Why so serious? Let's put a smile on that face. - The Joker

"Why so serious? Let's put a smile on that face."

The Joker Humor

"All you care about is money. This town deserves a better class of criminal."

"I'm not a monster. I'm just ahead of the curve."

"Madness is like gravity. All it takes is a little push."

"Everything burns."

"Never underestimate the power of a good laugh."

"Laughter is the best medicine."

"A good laugh is the best medicine."

"Laughter is contagious and wonderful."