My biggest challenge for my last job, not my current one, was upset customers at the bar. I was a bartender, and at a movie theater, we're a bit more strict than a regular bar, so we had a lot more rules. The biggest challenge was people being upset about following the rules, but I always tried to offer them solutions. So one simple example was, you can't take two drinks into the theater, so I would offer them to take a shot at the bar, and then they can walk away with their one drink that they are allowed into the theater.