The ideas that places like Impact Learning teach to customer service teams encompass many different parts of the job. In some ways, customer service is one of the hardest things to do, and there are a vast amount of sides to everything. On the other hand, though, you can really boil it all down to one basic idea: Everything that you do needs to be about helping the customer have a positive experience.
This is the way that you should look at each decision that you make if you work in this industry. Is what you are saying really going to help the customer with their problem? Are there other things that they have not even asked for that you could do to make the experience better? The answer should be yes for each customer, each day. If you are doing something that is not negative but that is not necessarily positive either, staying right in the middle where things are easiest, you need to know that you could do more.
This is part of what makes your job so hard. When customers are being unreasonable and yelling at you, you cannot yell back and lose your temper. You cannot take everything personally and feel offended by what they are doing. You just have to swallow those feelings and do whatever you can to make their experience as positive as it is possible for it to be. In the end, they are going to appreciate it, and this will help the company.