#2 Power supply.
You will over tax the wiring in your building. You will plug too many appliances into one circuit and the breaker will disconnect when the amperage demand exceeds its tolerance levels. This usually coincides with peak business periods. Let’s say you’re serving coffee, toasting bagels and heating soup for lunch all at the same time, there is a line out the door and your four service people are moving as fast as they can. That’s when the lights go out, the coffee is suddenly cold, the toasters stop toasting and the stereo goes dead. To make it more realistic throw in the probability that you’re on the beach taking your first morning off in weeks and no one at the restaurant knows where the breaker box is or what to do if they could find it.
Hint; Take your pick; you could balance the amperage of all your appliances to fit all your plugs and breakers or you could just respond to this eventuality one black out at a time like we do.