If one ever wanted proof that "Hell Is Other People", just work retail during the month of December.
See, during Christmas, the normal trickle of rude customers turns into a wave of self-important holiday sociopaths willing to do anything (from slandering you to your manager to trampling someone) just to get what they want.
Take the poor bastard in this video for instance. The unfortunate assistant manager of this Wal-Mart decides to shut the entrance to the store a few minutes before closing on Christmas Eve. But he failed to take into account the handful of people bold or insane enough to literally wait until the last minute on Christmas Eve to shop.
What follows next is an exchange that might make you lose faith in humanity. One of the men accuses the manager of discrimination, and the constant sight of other, prompter customers inside enrages the would-be shoppers even more. They continue to threaten the manager with promises to talk to his superiors, unaware that they couldn't possibly make his life worse. He's already working the closing shift at Wal-Mart on Christmas.
If you have the stomach to make it to the end, your reward will be a sweet dose of irony — specifically in the form of the man who doesn't know what discrimination means making a racist comment about Mexicans.
… and to answer your question: yes, I have worked in retail.