I work at a licensed store at a university and on my shift Thursday there was a problem with our credit card reader. Turns out, the system was down for the whole university, not just starbucks.
Before we knew that it was a school wide outage, we took a minute to try to figure out the problem with it. While this was going on, an older woman (50s maybe) was complaining about how it was taking too long, and proceeded to ask in a rude tone “So should I just go somewhere else or can you figure it out?” My coworker politely said “If you dont have a different method of payment there’s nothing I can do.” The Karen stormed out and screamed “This Starbucks just has HORRIBLE customer service and I CANNOT believe you guys werent trained to handle these issues.” The rest of the line was full of younger college students and they were sympathetic and understanding.

It always tickles me how every single rude encounter I have with a customer is an older person, while college students are very pleasant to serve.