Mr.-I-am-so-above-waiting-in-lines-because-I-am-special was quite cranky that I hadn't moved faster. As I was wrapping up his order, he leaned over and said, "Ma'am, did you know you are a real bitch." I'm sure he was waiting for me to break down in tears or get angry and yell back at him, that would have made his sorry little day. But in the interest of "the customer is always right," (and unholy mischief) I hitched on a super-big grin and replied, "Thank you SO much for noticing." This guy turned I don't know how many shades of red and I could clearly see the dilemma rolling around in his head. He had no words. He couldn't go report me to the manager. (who was my father no less) What was he going to say? "She was mean to me, she actually had the nerve to smile when I called her a bitch. Nope that would never work, so he snatched his receipt, turned on his heal and retreated as I stood back and chuckled.
At the age of 16 when I started out in the world of retail my father gave me some sage advice. If a customer is mean or rude then I need to be all smiles and politeness. If I were to get angry or upset, it would just add fuel to their fire and give them what they were looking for. Essentially they would own me. Now when I stand in line at the grocery or wherever, I sometimes get annoyed that the clerk is taking too long but I also respect that they may be having a tough day and try to be as polite as can be in return. I figure I'm just passing on the goodwill for not letting people get to me in the past.
My family, to this day, is greatly amused by the story and it has become legendary. My grandma loves to tell her friends how I didn't miss a beat and stood up for myself.