Messing up at work is something that everybody does now and then, and dealing with the fallout doesn't always get that much easier. While all workplace mistakes come with their fair share of embarrassment, it has to be said that the potential level of mortification is multiplied when we talk about customer-facing jobs. These are the roles where employees don't just have to prove their professionalism to management, but also to random members of the public. Failing at that means double the consequences.
Some people will be more understanding than others when their server or similar seems to be having a bad day, but it isn't always easy to predict who is going to take a mistake in good faith and who is going to give a hard time about it. In times like these, the worker in question is going to have no choice but to find out what kind of customer they are. It can feel a lot more difficult to own a slip-up than it can to deal with a time when the customer is in the wrong, as it is a matter of competency.