I've been going to this post office for 15 years and over the last 2-3 years the service has gone downhill. The customer service/cashiers used to be very friendly and helpful. But I think most of them have retired. It's a fairly new staff and most of them seem really unhappy and turn their unhappiness towards customers.
The prices have really gone up too. Now for many packages the only way you can send them is Priority, and ground or parcel post isn't available. (If you try to price a package at USPS.com, Priority is the lowest cost service they'll quote.)
And the customer service/cashiers frequently treat you like a criminal. There's one woman who demands to see an ID if you're paying with a credit card. I hated that so much I paid with cash. But then she held up my bills to the light to see if they were counterfeit. Really? So when she gave me change I held up the bills she gave me pretending to see if they were counterfeit. She didn't like it too much, but at least she knew how I felt.
Still there is at least one person who is very friendly and provides excellent service. But she is the exception and not the norm there. I've had a couple of nasty encounters with some cashiers that would take too long to explain here.
I try to support the post office because I know it is in financial trouble through no fault of its own, but it's hard. For example, if I have an amazon pre-paid return I chose to return it using USPS instead of UPS to give the post office some business. But then one of the cashiers wouldn't accept a package with a pre-paid label because she said it was overweight by two ounces. She told me to go home and ask amazon for another label. I did that alright. I asked for a UPS return label and UPS took it no problem.