If you've ever worked in retail , you know the struggle of dealing with that one customer. You know, the one who always has a complaint, never waits patiently and somehow manages to make every shopping trip into a full-blown scene. For this employee, that customer was this entitled Karen who made it her mission to cause chaos to him and his coworkers every time she walked into the store. She'd yell, she'd argue, and she'd make everyone's day a whole lot worse. Just because she could. But fate h…