The cashier handling a long line with a smile knows more about patience than most books.

Some things can only be learned by doing them repeatedly under conditions you do not control. Holding steady through a line of impatient people is a real skill, built the hard way, and no amount of education hands it to you. The people who have it often go unnoticed entirely. Watching closely teaches more than reading about composure would.

Pay attention to someone doing a hard ordinary job well this week and notice the actual technique. How they pace themselves, what they decline to react to, how they reset between people. If you get the chance, ask, because people like being asked about what they are good at.