Too bad you don’t have my mail carrier. He’s dependable, friendly and goes out of his way to accommodate his customers. Whatever one might think of the level of pay, postal work is generally not easy, particularly on the evening and midnight shifts when most of the mail is moved- those parcels and sacks of mail do not sprout wings and move themselves. Most postal employees have to work up a good sweat to receive their “welfare”.
My guess is that the USPS work rules are as onerous or more so than any of their competitors. The idea that postal workers may have to “work up a sweat” during the course of their duties should be a good thing. As for your mail carrier being friendly, any group has a few good workers. I think if you polled people you might be surprised that most folks would not share your enthusiasm for their letter carriers.