Seriously? "No offense but..." usually proceeds an offensive comment. You know the comment that is too personal and never actually asked for. It usually comes out of the mouth of someone who boosts about being brutally "honest" or "real." Frankly, sometimes it is just "real" mean or "honestly" rude.
Don't get me wrong, I value honesty. It is necessary to have real relationships. I also know that I have stuck my foot in my mouth more than once and have wanted to go back and erase something rude that I have said. However, generally I try to be nice and I think most people do too. I don't think that it is over-rated. I feel like it is worth the extra effort to find a way to give someone honest feedback with a little finesse.
Sorry, just one of my little rants! By the way, I don't really like your hair. No offense.