What the hell are you talking about?

As a matter of fact, the most heard sentence in the show is: "What are you doing here?", whenever two people meet. It's becoming annoying when, like me, you watch the show 4 episodes at the time.
"I don't give a *beep* is also very often used.
Instead of the regular "gag reel" they should put all those "What are you doing here?", "What the hell are you talking about?" and "I don't give a *beep* from a single season into one single clip. It would run several minutes, I'm sure. It would probably put the writers to shame though.

"Louis?"

Yafai M.

Also:

"What did you say?"
"You heard me"

"What is that?" (after paper/file is tossed on asker's desk)
"You know what it is"

"What did you do?"
"You know what I did"

"Why did you do that?"
"You know why"