Sometimes it is best to hang up because once you have said something it cannot be taken back.. Sometimes you have to ask them to hold for a moment so that you can bite your tounge, you might have to put yourself in their shoes, things may have turned out very badly for them, the shirt may have been very important to them, like a job interview. Just close your eyes take a deep breath and count to 10 slowly....and exhale... easier said than done!!!!!!

I don't think you should ever hang up on a customer, no matter how angry they are. Customer service is a tough job, so it's essential that you learn to remove yourself from the negative emotions of an angry customer. Remember, they aren't furious with you, but with the situation. If the error was yours (or your company's), you need to reassure them immediately that you will do everything possible to make things right. Your goal here is to turn an unreasonably furious person into your raving fan by going above and beyond what he/she expects in terms of service. Think of it as a game. If you manage to defuse an explosively angry customer, you win!

Listen.

Angry customers want to be listened to and taken seriously, more than anything.

Barry Moltz wrote an excellent book about customer service and dealing with angry customers, and in it he suggests not just assuming the "customer is always right" because that may not be true.

Instead, listening and taking the customer's anger seriously and dealing with it is the best course. Customers want to know they are being heard.

The book is called BAM: Delivering Customer Service in a Self-Service World.