I think if we use someone's name, it usually because it's very deliberate on our parts. For example, when it's in any commercial setting, I'll make a note of the person's name to accomplish at least 1 of 2 things: First, that they can't get away with poor customer service because they are no longer anonymous, and second, that if they like that personal crap, then they'll think I'm being personal/nice and might treat me better. Win/win.
To tell you the truth, on phone calls, I almost always use it strictly in the first sense. The CSR usually opens up with something like "Hi, this is Paul, how can I help you?" I write that down right away. Then after we troubleshoot the whole problem-- and without me saying his name the whole time-- I always end with something like, "Thanks, Paul. I appreciate your help." Just to freak him out. But also to let him know that people are paying attention, and he is responsible for what he is saying.