Pray for the people who serve your food. It gets harder to be rude to someone you’ve prayed for.

Rudeness to staff depends on not quite seeing them as people with a whole day attached. A few seconds of deliberate goodwill closes that gap and makes the sharp comment unavailable to you. It is not a rule you follow; the contempt simply stops being accessible. You cannot hold somebody in mind kindly and then speak to them like furniture.

Try it this week at the counter or the drive-through. Ten seconds before you order, something good for whoever is working. Then notice what happens to your tone when the order comes out wrong.