While I will say that there are unquestionably some good and able people in the Post Office it is the very nature of the "service" that disallows improvement, ie. don't rock the boat if you work there. And of course the PO has a monopoly on snail mail.
That being said I can attest to the fact that my local PO's personnel carry on the spirit of the classic Lily Tomlin telephone operator character: "We don't care. We're the phone company - we don't have to."