1) Staff who are no call/no shows - Now that I'm a culinary arts teacher, this really isn't too much of a problem. After all, I have a captive workforce i.e. my students ... so if a student cashier is absent, it's generally not a problem. All of my level II and III students are cross trained, so I simply reassign one of the other kids to a vacant slot ... but in the real world of the commercial kitchen, it was a pain in the you know what to have to have no calls/no shows ... and as the general manager of my last restaurant kept the establishment perpetually short staffed to save on labor costs, staff absences really caused problems.
2) Teenage hormones - Yesterday one of my student counter servers kept forgetting his job because his girl friend came to visit during lunch. They stood at the end of the service counter(of our student operated restaurant) and held hands. The student cashier had racked up three orders before I spotted what was going on. The counter server was reminded of his job ... but his mind was lost in a romantic fog. While casting looks of longing at his lady love, he poured a diet pepsi instead of a rootbeer and served up pizza bread instead of a bean burro. I had to put the kid on dish tank and replace him with one of my paid adult staff.
3) Cleaning ... one of the hardest things about being a culinary arts instructor is that I keep getting kids who have a misconception about what we actually do. Some sign up because they love to eat. Some of them actually like to cook. None of them like to clean. Some of the girls in particular don't want to soil their hands by picking up a scrub pad, so they try to clean pots and pans using a hose. Having failed to remove globs of food from the pot, they either put the dirty item in the dish washer or they bat their eyes and play "poor little princess" in the hopes that one of the guys will do their cleaning for them. I find this incredibly annoying.
I have largely solved this problem by tying a cleaning grade into the production grade. Before I assess a student product, I inspect their work stations. Since each student has an assigned job, I know precisely who was responsible for not wiping down the counters, cleaning equipment, or washing tools ... and the individual grades reflect this.
Since some students don't appear to care whether they're downgraded for not cleaning, repeat offenders have been tasked with additional cleaning responsibilities: drain and clean the deep fryer, dismantle and sbrub the charbroiler etc.