It is interesting how this is a good analysis story for HNers. It is sort of a nice open-ended parable and it seems how it is interpreted tells something about the person interpreting it.
Some identify with the waiter -- they imagine making a mistake and someone yelling at them and them thinking "what a pompous ass".
Others identify with the CEO -- they imagine how they would have pity on the waiter (assuming they are somehow superior because they have $X more money in the account or that many employees they control), or how they are leading by example and not showing their anger (yet still are cursing the hell of out of the person in their head), some are worried about _looking_ bad so they imagine acting well if someone is watching ...