Spock and McCoy in “Unfinished Business”

Spock

Doctor, I am well aware of human characteristics. I am frequently inundated by them, but I've trained myself to put up with practically anything.

McCoy

Spock, I don’t know too much about these little tribbles yet, but there is one thing that I have discovered.

Spock

What is that, Doctor?

McCoy

I like them - better than I like you.

Spock

Doctor, they do indeed have one redeeming characteristic: they do not talk too much.