Sméagol: We knows safe paths for Hobbitses. Safe paths in the dark.
Gollum: Shut up!
Bilbo: I didn't say anything.
Gollum: I wasn't talking to you.
Well, me, it's nice talking to myself
A credit to dementia
Someday you too will know my pain
And smile its black-toothed grin
If the war inside my head
Won't take a day off I'll be dead
My icy fingers claw your back
Here I go again!
—Megadeth, "Sweating Bullets"
Romana: Talking to yourself is a sign of insanity, Doctor.
Fourth Doctor: Insanity? Me? That's ridiculous! I'm a stabilizing force of the universe!
Seventh Doctor: I just think one of us could do a better job alone. "Too many bakers spoils the crust."
Sixth Doctor: And what is that supposed to mean?
"Barry, is that how you get ants? Yes it is, Other Barry, yes it is."
—Barry Dylan, Archer
O'Malley: GET OUT OF MY HEAD!
Doc: Technically, it's my head. But I don't mind sharing!