A good lifeguard says “walk, please” for the hundredth time with the same patience as the first.

Repeating yourself without hardening is a skill, and it is harder than the technical part of most jobs. The hundredth time is the first time to the kid hearing it, and letting your tiredness leak into your tone is how a job slowly makes somebody unpleasant. Patience here is maintenance of yourself as much as kindness to them. Nobody deserves the accumulated weight of the previous ninety-nine.

Catch the next moment you are about to repeat something for the tenth time and reset your tone deliberately. Say it as though it were new. Afterwards, notice whether it cost you anything real.