If there was ONLY mail for Smith Circle, I'd blame the mailman. But, if it was mixed in with mail for Smith Drive, then that's an issue with them sorting it at the post office, and bundling it incorrectly.
My current address is 807. I'm in one of those areas that's rural enough that all the mailboxes are on one side of the road, my side. So the people on the other side have to cross the road to get their mail. My neighbor right across the street is 800, and his mailbox is next to mine. The only other 80X number is a newer house that's directly behind my lot, but with the odd way some large lots were subdivided around here, his driveway is a shared one, and his mailbox is about 400 feet down the road. I'll occasionally get mail for 800. I don't think I've ever gotten it for 805, but have gotten it for some 7XX numbers on occasion.
My old house was 12112. Two doors down, was 12212. The one in between us was 12200. Needless to say, I got 12212's mail quite a bit, and they also got ours. And that mailman had been on the same route a good 30 years or more!
The 12112 property had been in the family since before the Civil War. I have a few old letters that were in a metal box, from the 1920s. Considering nowadays they'll screw up your mail even when it's addressed property, could you imagine the nightmare it would be, if people still addressed them the way they did back in the old days?! I think zip codes first came out in the early 1960s, but I guess if you go back far enough, they didn't even have house numbers assigned yet! Glenn Dale (that spelling came out in the 1960s) was really small back in the 1920s, so I guess everybody knew everybody. So they probably just referred to places as "The Wood House," "The Old Haney Place" or whatever.