I'm writing a unique MUD, and It was surprising to me when I posted some bug reports I'd made and it identified things I didn't complain about. "User had trouble with X" and then suggested mitigations for those problems. I ended up rejecting a lot of them because I knew I had different mitigations coming eventually, or it was working that way for a reason...

But it was pretty eye-opening to see how good it was at watching a user struggle and identifying possible fixes.