3
Erroneous "not available on your instance" message
(sh.itjust.works)
I've been encountering an increasing number of links which "may not available on your instance", even for posts which I know are available on my instance.
Here is a absurdly silly example where I used a remote link to one of my own posts. It can't be unavailable on my instance, because I made the post! :)
FWIW, I think this phrasing is understood differently depending on region. In the UK, and especially the northern counties in England, this is mostly understood to be a humorous exclamation of disbelief rather than anything aggressive.