A polite way to to respond to thanks. Implies that the other person is welcome to ask for any other favors. Synonymous with no problem.

The only phrase in the english language that has no correct response other than changing the subject entirely.

Something to say when a co-worker sneezes and there are others in the room. Always gets a laugh due to its incongruity.

For tonz 'o laffs, be prepared with a list of other pointless customary statements for when the person sneezes many times in succesion, e.g.
yes please
fine thank you
I'm sorry
no thank you