Surviving the dinner rush at a burger spot trains a calm under pressure most office jobs never will.

High volume work under time pressure trains something that cannot be taught in a calm room. You learn to hold several tasks at once, to keep moving when everything is behind, to stay civil while somebody is unhappy with you. Those hours look unimpressive written down and produce a steadiness most people never develop. The pressure was real and so is what it built.

Name the skill rather than the job when you describe it, to yourself or to anyone else. Notice where that calm turns up in other places. You came out of those shifts carrying something you did not have before.