Would you have done this...?

The way I see it is in a public business place like that you should be capable of controlling yourself and you should do it. In an informal private affair where it's something like you and somebody in your neighborhood that you don't like, you can do whatever you want. But in a position like that where it's not just you and him and there is other people relying on you to do your job, then I think anything worse than sarcasm is ridiculous. Refusing to serve them, throwing food at them, punching them, etc. Why? Just suck it up, be the bigger man and move on.