Is the world turning mean?

I've found that most of the customers that I have to deal with on a daily basis are just plain mean. I'm so tired of being abused! Just today a man couldn't understand why I couldn't just swap out his returned item for another different item that was the same price. Couldn't get the concept that we have inventory to maintain. You can bend over backward and not make a difference. It gets so difficult to give a smile when you don't get a smile in return. I've noticed that they use the least little thing to try to get a discount. Sure the economy sucks, but do you have to pretend you didn't get good service just to get a free ride. I get to hear all the sob stories about other employees that didn't treat them right and they want to be compensated for it. Put your big girl panties on and deal with it!