At a register, you learn fast that a rude customer is usually carrying a bad day into your line.

Very little of what arrives at a counter is about the person behind it. People turn up mid-argument, worried about money, late for something, and the first available human gets the overflow. Working out that you are standing in the path of somebody else’s day, rather than being judged, keeps the job from eating you. The rudeness is real and it is not yours.

Practise putting it down this week. Be polite, finish the transaction, then take one breath and let it go before the next person. Tell a colleague if one gets bad, and if anybody crosses a line, that is a manager’s job rather than yours.