What's the difference? Empathy vs Anger.
If you can get them: appreciate their point of view, understand their concern, and communicate that you get them, they (customers) will feel like they are getting great service.
The other GET THEM! is perhaps how you feel when you've had a few tough calls in a row and are frustrated. But as you know, taking it out on a customer will come back to um, well, bite you, later on.
Take a deep breath, take a short walk, or pop a squat and focus on your next caller with a smile on your face.
Winning customers over is the best revenge!