Empathy
We all know that the best suppliers anticipate your needs before you are able to fully articulate them. It goes beyond putting yourself in the other person's shoes and walking around in them. Because you can never be them, you can only be you. So sometimes you need to drop your beliefs, expectations, and view of the world in order to know what is the best thing to do for your client. To understand where they are coming from and to make sure they get where they need to be.