I work the front desk of a hotel so I've had just about every experience there is in customer service. Had money thrown on the desk, been threatened with physical violence, been accused of racism, Insulted because of my voice or appearance, been accused of ageism, been raided by a swat team, had a couple doing demonic rituals, and creating shrines around the property, had drug dealers, prostitutes, homeless people, people clogging toilets on purpose, people screaming at me because they booked the wrong room type on a sold out night, etc.
The only thing I think I haven't seen is a murder, or found a body.