Perhaps we have just been lucky, judging from all the complaints about the Post Office that I've heard over the years, but we have had very good service from the Post Office for decades. Occasionally we do receive something that belongs to a neighbor, or a neighbor gets something of ours. But zero mistakes is practically impossible, so I really can't complain.
When we were first at our previous house, our mailman was Melvin. He couldn't have been nicer, knew most of the children on the street by name, and tolerated the kids "helping" him by pushing his little cart along the sidewalk. We were upset when he said his request for transfer to the post office in his own neighbor had finally come through. But he was replaced by Victoria who also couldn't have been nicer and was just as good at the job as Melvin was.
If possible, you should get to know your service people. Knowing Victoria saved me considerable hassle when my wife was out of town and I found a note in the mailbox telling me there registered mail awaiting her signature at the post office. I went there to sign for it, but the clerk said, "I don't think you're trying to pull a fast one here, but you don't look like a Molly." So, I asked if Victoria was there, and when she came to the counter she said, "Yeah, that's him," and I got the mail without further delay. We used to give her a lot of old TV scripts (printed on one side, blank on the other) which she gave to her daughter's pre-school for the kids to use as scrap paper.
The UPS guy at that house, Salvador, was also terrific. He even remembered what I drove, having seen it parked in front of the house all the time when I was "on hiatus" (that is, unemployed between shows). One day when I was on our street but a block south of the house, I saw the UPS truck coming toward me. Salvador started blowing his horn and waving at me to stop. So we stopped with the driver's windows facing each other, Salvador in his UPS truck and me in my van, and he handed me a package. Good for me because I got it; good for Salvador because he got rid of it.
I could, but won't, go on.