
Well, it would be SELFISH of me
to keep it.
The Big Bang Theory Season 10, Episode 10

You're a completely SELFISH human being
and a physical and moral coward.
The Big Bang Theory Season 8, Episode 6

Because you were being SELFISH.
The Big Bang Theory Season 10, Episode 10

Sheldon, you can't be SELFISH.
The Big Bang Theory Season 1, Episode 14

or a SELFISH reason?
The Big Bang Theory Season 12, Episode 20