Ugh. I hate to hear about things like that. On behalf of all decent former and current employees, I'd like to apologize. It's been my experience that the atmosphere is much friendlier in rural and small town post offices. One problem with postal retail clerks arises out of the very nature of postal work. The majority of postal clerk work is done at night, and can be dull, repetitive, and physically unpleasant. The best way to escape that is often to bid, by seniority, on a window clerk job. Sometimes that window clerk isn't the best suited to deal with the public.
You also mentioned the DMV. The last couple of years at the local DMV we've had an employee, a young black man, who is an absolute joy to deal with. A person like that can be like an oasis in the desert, and I hope he will be properly rewarded for his competence and pleasant nature.
“You also mentioned the DMV.”
Actually, here in CA, the DMV is light years better than it has been in the past. Years ago, I worked in San Francisco, so I went to the DMV office in Golden Gate Park to renew my driver’s license on my lunch hour. Bad mistake. Didn’t take a good look around until I had already surrendered my current license and commenced taking the written. When I got back into line, I was confronted with a triple fold line that stretched the full block between the two ends of the office. People were taking the test in line and I remember one Hispanic was having his pre-teen daughter looking up the answers in the handbook and giving them to him as they stood in the line. At 4:45 a big fat woman stood up from her desk and announced that it was time “to get the line moving so they could close.” Every clerk in the place opened a window and in the time remaining, they cleared the entire line. Oh, the Hispanic guy flunked the test and was pissed off because he didn’t have a license to drive his car home!