The problem we started from
A college break is short and fixed. The canteen rush is short and fixed too, and it lands at exactly the same time for everyone. The result is a queue that can take a third of the break, followed by eating in a hurry.
The canteen has the mirror-image version of the same problem: a crush of people all arriving at once, orders taken verbally under time pressure, cash handled at the counter, and no way to know what to prepare until someone is standing in front of you asking for it.