Honesty: helpful or hurtful?

I have a topic on my mind that has been bugging me all day! Which is better/worse: to be nice & don't tell a person something because it may hurt their feelings or to just be honest with the person & not keep them wondering in the dark...?
I have been on both sides of the spectrum, so I do know this is a tough decision. However, I do think honesty is always better. I've been honest with people just so they don't have to feel clueless or "waiting", I've been told my flaws as well, which at the time didn't feel so nice, but I now know its better then wondering. But most of the time I'm left in the dark, which I hate.
I know I've said it before, but in the love & relationship department I just don't have any luck, unless bad luck counts! Most stories start off with "so there's this guy I like/liked for a while...." and ends with "he says I'm a good friend/ one of the guys..." or "he always has excuses not to hang out ..." the story is always the same, but I guess I just am optimistic or maybe just plain stupid.
So, in the end, I guess what I'm really wondering is if I really want to get left in the dark/blown off time after time or do I really want to hear whats wrong with me/why I'm just not appealing ...? Is there really a good answer? I guess only time will tell!