Quote by Marty McFly

"This is heavy."

"There's that word again, 'heavy.' Is there something wrong with the Earth's gravitational pull?"

"I'm your density. I mean, your destiny."

"You're my best friend, and I care about you, but don't ask me to do this."

"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."