Hostility between labor and management is epidemic at the USPS. This will probably be more or less true no matter which post office in the US you work at. Management manages almost solely by numbers(mail count, time the carrier leaves the office, etc) and not through level, well thought out exchanges of information with the workers on the floor. Based on the mail count (which doesn't cover packages or full coverage mailings- mailings which go to every address on the route), they have a computer program which tells them which times you should leave and be back. Carriers can spend a great deal of time arguing with management why the information, or more often, the expectations from it, are wrong. And when you don't perform according to managements' wishes or the computer's data, it's your fault, not managements' or the computer's. There are other things, too, but I don't have time to go into them more. To me (and to a lot of letter carriers) this is the big one.