Why are people, that are supposed to be helpful and friendly, rude?

Last Friday I had enough of rude people. I had a problem with the ADSL connection so I called my provider Libero for some needed assistance. I got to hear the latest Shakira's hit appropriately called 'Tortura' for 40 minutes. When finally someone decided I had suffered enough, I got a feminine voice on the other side asking 'What do you want?'. I was amazed by the way she answered the phone... I asked if I was interrupting her dinner. This exchange started our conversation on the right foot. From then on it just got worse.
I believe that Luisa had a very developed technique in how to 'unserve' customers. First, she makes you feel guilty about calling and then she makes you feel the dumbest person on earth for having the problem you need help to solve.

I'm tired of bad customer service! This episode was the culmination of a string of experiences to forget. I have decided to fight this war and to give honest feedback, in a educated way and with the help of irony to all customer service representatives that don't know the meaning of the word friendly or helpful.