Working in customer service, hospitality, retail, or any other field that requires you to have human interaction with Karens on a daily basis, gives you a strong backbone you never asked for, and bucketloads of apathy. At first, you feel like a failure when a customer screams at you, demanding a free refill because your coffee tastes like the back of a dump truck. You realize it's ridiculous that a total stranger has the power to make you feel like a blundering fool, all over a cup of coffee. E…