How someone treats a server on a slammed Friday night tells you more than anything they post.

Behaviour under no social pressure is the honest version. Anyone can be pleasant to people who matter to their reputation, which is why the real information is in how somebody speaks to a person who is rushed, tired and not in a position to object. There is nothing to gain from it, so what you see is simply who they are.

Watch it in other people, and watch it in yourself when a shop is slow or a shift is bad. Being patient when it costs you something is the version that counts.