There is a concept in Buddhism known as "Sangha." In short, it refers to the community of believers. Any time someone wants to learn something new, or change their lifestyle, or even kick a bad habit (or start new ones) it's good for them to surround themselves with like-minded people for support. You see this everywhere -- Weight Watchers, AA, Sunday Mass.
The same holds true for changing your customer service skills. A visit to any call center break room will find that reps like to segregate themselves into different groups. One group likes to talk about life outside of work, another group likes to talk about positive customer interactions, while another group likes to complain and criticize customers. Beware the last group.
If you spend time with customer service reps who have negative attitudes, then it will be easy for you to adapt that attitude as well. First, you'll want to feel part of that group so you'll begin to share your negative experiences. Soon, negative customer experiences will become part of your work day. You'll begin to look for stories to share with your new lunch mates. You'll start to look at your job negatively.
Instead, have lunch with those that have a positive outlook on their customers and their jobs. Soon the opposite will start to happen. You'll begin to see the customers in a more positive light and chances are you'll start to enjoy your job a lot more.
So this week when you are at work and you have the choice of sitting with co-workers who complain or those who don't, sit with those who don't complain. I bet in a few weeks you'll start to see your job differently. This is the secret of Sangha.