The People Problem

Over the past week in my job I have found it increasingly difficult dealing with customers. I've found my self thinking thoughts like "I really wish I didn't have to put up with this customer.", without really understanding what they were dealing with. I was forgetting what I had posted on here before. I am aware, I am listening, I am comprehending. If I were to have a better understanding of what was going on in their heads, I would have been able to find the real problems and easily resolved them. What I have been doing is wrong and I wish to change that behavior and start treating customers more as human beings than "problems".