It's all in a person's attitude. Even I have a hard to listening to people who are harsh, insensitive and arrogant. I have a hard time valuing their input, even if they are right. It's not as if I want people to commend everything I do. In fact, I am suspicious of people who seem too eager to flatter and please.
True friends care enough to tell a person the truth.
But first and foremost, they care. Take the example of teen-agers who abuse drugs. Everyone knows that using drugs is wrong. It is illegal. And since drug abuse harms the body, many of us also consider it immoral.