That made me laugh, over and over and over again

Sheldon: Fine, what do you want me to do?

Leonard: Well, smile.

[Sheldon smiles]

Howard: Oh crap, that’s terrifying.

Leonard: We’re here to see Koothrappali, not kill Batman.

Howard: Try less teeth…

[Sheldon smiles again]

Leonard: Close enough, come on

The Big Bang Theory - 2x04