Say it? Or not?

I have always heard of people saying that sometimes, some things are better off not saying to the party involved cos the ugly truth is so vulgar and hard to accept that the affected party has to end up staying in an illusion to hide from the fact. By telling them the cold hard fact, things may be much worse than one can imagine.

I used to be upset when people tell me facts, and really ugly facts about myself, about how lousy I am, or how bad is my attitude, but now, instead of being upset, I analyse to see if the statement made is valid. If it is, I make it an effort to change it but if it is an invalid statement, I ignore it. I think I fully understand how the truth hurts when said cos I can feel it myself. If the affected party is just another person, then there is no point blurting out truths cos one will make himself a targetboard of hate. But when the affected party is your close friends, loved ones? Say it, and all hell will most prob break loose, but not saying seems morally wrong.. How should this then be solved??

Interpersonal relationships can be so difficult to handle..