Who shall I shoot? You choose. Now, listen very carefully: where's your coffee? You've got coffee, haven't you? C'mon, everyone's got coffee! Spill the beans!

This I choose to do. If there is a price, this I choose to pay. If it is my death, then I choose to die. Where this takes me, there I choose to go. I choose. This I choose to do.

Some people are confident because they are fools. Leonard had the look of someone who was confident because, so far, he'd never found a reason not to be.

After a while, another voice said: One, two, three, four- And the universe came into being. It was wrong to call it a big bang. That would just be noise, and all that noise could create is more noise and a cosmos full of random particles. Matter exploded into being, apparently as chaos, but in fact as a chord. The ultimate power chord.

I can't be talking to a tree. If I was talking to a tree I'd be mad, and I'm not mad, so trees can't talk.

Credulous: having views about the world, the universe and humanity's place in it that are shared only by very unsophisticated people and the most intelligent and advanced mathematicians and physicists.

Ninety percent of true love is acute, ear-burning embarrassment.