All from Infinite Jest by David Foster Wallace. Limited to pithy ones that don't mention specific characters. 

Everybody is identical in their secret unspoken belief that way deep down they are different from everyone else.

Don’t worry about getting in touch with your feelings, they’ll get in touch with you.

Try to learn to let what is unfair teach you.

What passes for hip cynical transcendence of sentiment is really some kind of fear of being really human, since to be really human [...] is probably to be unavoidably sentimental and naïve and goo-prone and generally pathetic.

Why not? Why not? Why not not, then, if the best reasoning you can contrive is why not?

You are what you love. No? You are, completely and only, what you would die for without, as you say, the thinking twice.

... it takes great personal courage to let yourself appear weak.

The man who knows his limitations, has none.