Customers are easily the worst part of any customer service job, followed closely by arrogant unqualified managers. The two make a dynamic duo when you're unfortunate enough to endure them simultaneously. The Karen, an unstoppable force of rage and fury, and the manager, an unmovable brick wall of utter density. Like Batman and the Joker, they are eternally locked in an endless struggle—and you're stuck in the middle. (It's no wonder that, in these industries, you spend most of your time off ju…