Big Bang Theory Quote
Penny: (knock, knock, knock) Sheldon!
(knock, knock, knock)
Penny: Sheldon!
(knock, knock, knock)
Penny: Sheldon!
Sheldon: I bet that started off as a joke, but by the third one, you realized there was something strangely enjoyable about it.
Penny: Yeah, I kind of want to do it again.
Sheldon: I don't recommend it, you'll be doing it the rest of your life.
Quote from S08E21 - The Communication Deterioration