Well, if you don't add examples and a thorough explanation, then the author can't really improve and that pisses them off. I'd be annoyed too if people kept telling me to improve on something, but expect me to figure it out all on my own.
I do know what you mean, though. If there's something I've dealt with, then it's reviewers attacking me over one of my reviews.
Aw, I don't really do the whole 'friend request' thing much. I mostly add people I know really well if they want me to, but that's about it. XD