I'm 20 and I'm a barista at a restaurant. It's regular-sized, 18 tables, 4 seats, that makes it 72 people that fit in it. It gets full very often, and I have to prepare all the drinks. Sometimes people come in little by little, sometimes they come in waves, and sometimes the restaurant gets full in 15 minutes. People who work in restaurant might know this feeling, seeing everyone coming in at once and go "ugh here we go". 

Everytime I see people coming in, no matter if it's a table for two or a table for ten, my body is tense, my hands shiver, and my mind is starting to go a thousand miles an hour, as if I had to prepare a hundred orders at once. I hate this awful feeling. 

To be fair, it's my boss's fault too, because we NEED more personnel.