Recently, I was in a line at the supermarket where the person ahead of me took nearly 10 minutes to resolve a payment issue with their order (usually, payment takes 30 seconds to a minute). When that was finally taken care of, the cashier started scanning my items and said "thanks for waiting."
How do I respond to that? I feel like I could say "oh, it's no problem", but it was a problem. I was rather inconvenienced and was late to my next appointment. I don't want to be rude, but is there any way that I can be polite and prevent awkward silence without saying that the delay didn't bother me?