Your situation might be alittle different *blowitup*, I have a very good relationship with the ladies that run the place where my PO Box is. They will call me and let me know when my packages have arrived and I will let them sit there for a day or two if I'm not in a hurry to pick them up- sometimes they will even take my packages out of my box and lock them up for me in another part of the buisness- until I come get them. It's a pretty sweet deal. And they DO know what is in the packages, thats why they try to help me out so much.
As far as you having to have direct contact with people there when you pick up your packages- there really shouldn't be. It all depends on how friendly you want to be with the people there. But my PO Box is NOT at a post office- it's at a contract mail handler, independently owned. I would suggest you get one at the same kind of place, if you are considering getting one.