I've had a few hams classified as spam - mostly mailgroup messages and github notifications, generally weird e-mails originating from addresses that send lots of mail. Generally, nothing critical, or even important for that matter. I vaguely recall finding one or two somewhat important e-mails in spam years ago, but it happened so rarely that I don't even remember the details. I still have the habit of checking my spam folder every other month, but generally I'm very satisfied with GMail's filtering.
I have the same thing, a few issues of the Go Newsletter GitHub notifications have been marked as spam, nothing extremely important. There are usually ~5 "real" spam messages in there - to me a scientist, it's amazing that the system also recognizes scientific spam. I just have " In order to speed up the development of its journals, Science Publishing Group currently gives authors the Special Offers for paper publication: " in my spam folder, which has nothing to do with the actual Science journal and is just a predatory scam journal.
Could be that other GMail users don't know how to unsubscribe from GitHub/other notifications and mark these as spam to get rid of them which introduces false positives into the spam notification system.
In some cases unsubscribe links can be used to determine if a targeted email address is actively monitored or not. As a result it's not a good idea to click them for email that you don't remember soliciting.
