Why is it so difficult to deliver feedback?

I read an article about the importance of giving feedback and the difficulty of giving feedback. I couldn’t stop myself from drawing the 4 rules of thumb:

1. Feedback says more about the giver than the receiver
2. Feedback is a gift
3. Feedback is only useful (and used) when it is asked for
4. Once feedback is asked for, it is often no longer needed

The original article is worth reading