Electrical — damaged leads, overloaded boards, faulty appliances
Frayed cords on heavily-used appliances, daisy-chained multiboards, water near powered equipment. The reason wet areas get singled out: dry skin is a decent insulator, but wet or sweaty skin drops your body's resistance by around a hundredfold. The same contact that's a harmless tingle dry can be a can't-let-go shock when your hands are wet. Wherever hands are wet around mains-powered gear — a dishwash or prep bench, a salon basin, a cleaner's sink — wet skin is the everyday state, and wet skin conducts. That's why RCD protection there isn't belt-and-braces; it's what stands between a faulty lead and a fatality.
This is one hazard. Your register is the set that applies to you — under 20 questions, about five minutes, free.