Two of my favorite quotes/exchanges in the history of television.

[per_solo]

The Doctor: Don't challenge me, Harriet Jones. 'Cause I'm a completely new man. I could bring down your Government with a single word.
Harriet Jones: You're the most remarkable man I've ever met. But I don't think you're quite capable of that.
The Doctor: No, you're right. Not a single word.
[pause]
The Doctor: Just six.
Harriet Jones: I don't think so.
The Doctor: Six words.
Harriet Jones: Stop it!
The Doctor: Six.
[approaches Alex, whispering in his ear]
The Doctor: Don't you think she looks tired?

Followed, in another series/universe, by...

Inara Serra: You came to the Training House looking for a fight.
Capt. Malcolm Reynolds: I came looking for you!
Inara Serra: The war's over, Mal.
Capt. Malcolm Reynolds: You tellin' me that cause you think I don't know!
Inara Serra: I've just seen so many sides of you, I wanna make sure I know who I'm dealing with.
Capt. Malcolm Reynolds: I start fightin' a war, I guarantee, you'll see somethin' new.