
And Leonard just stood
there with a big, dumb
SMILE on his face,
The Big Bang Theory Season 12, Episode 12

SMILE.
The Big Bang Theory Season 7, Episode 4

Just SMILE and laugh.
The Big Bang Theory Season 5, Episode 4

(LILY ALLEN'S "SMILE" PLAYING
OVER SPEAKERS)
The Big Bang Theory Season 1, Episode 1

Wipe that smug SMILE off your face.
The Big Bang Theory Season 9, Episode 9