This is getting a little off topic, but I just wanted to share the worst example of customer rudeness that I've encountered. Sure, there are others who are demanding, angry, prone to fits, etc, but this one guy stands out in my mind because I felt like he was treating me like a machine.

I used to work in a photo lab. Customer comes in, puts his photo pick-up slip on the counter. I read the number, go get his prints, take his credit card, and hand him a pen. He signs the receipt, takes the photos, and walks off.

The whole time, he was talking on his cell phone. I didn't get one "Hi", or "Thanks", or head nod. Not even eye contact. I felt like an ATM. I also felt a little embarrassed to be eavesdropping on his conversation, but I suppose he didn't really see me as a person, so why should he care?