Lost My Cool at Work Today

I'm usually the model employee, always putting on my best customer service smile even when I want to strangle someone who's been in line too long and is ordering ten different flavors of the same thing. But today was a breaking point for me. A regular walked in who has this habit of making every single transaction into an ordeal. Today, they asked if we had every obscure flavor under the sun, and when we politely explained that some things were seasonal, their tone turned frosty as winter night. They started rattling off all sorts of accusations about why we didn't stock XYZ brand or whether our lemon ice was truly better than their homemade version. It felt like I was in a customer service death match. After they finally left, I leaned over the counter and let out this little whimper that made my co-worker burst into laughter. They reminded me to just breathe and count to ten next time someone pushes my buttons so hard it feels like pulling teeth just to get an order placed.