Unless spilling is a part of the gag, every coffee cup is always empty. Sometimes the camera angle even shows that it’s empty. I imagine it’s probably due to some actor’s guild rules or it’s a continuity trick so people don’t spill, but I mean they could at least put a weight in the cup, or clear water! Yeesh. It actually ticks me off, it doesn’t matter how good of an actor you are, the coffee cup thing drives me insane!