For me like someone else said I value truth cause it is reality, it is the only way for me to know that I am not being manipulated, deceived or that I am fooling myself to see things better than they are ( we are speaking about different truths here) or imposing my belief unfairly on other people, Knowing the truth I have a better perspective about things and I can use that knowledge to help myself and others in a healthy way.
Sometimes when being Truthful you might end up being seeing as tactless or blunt though when you aren't doing to harm anybody or to impose the way you see things in others your honesty would be appreciated.(Most of the time, at least)
That said, there are many Jerks that can get purposely nasty with words and claim after that they were only being "truthful" or "honest" while in reality they were just being obnoxious and nasty, to this kind of people just tell them to FUCK OFF or just ignored them. This are usually the most dishonest and rude you can find.
I suck with punctuations I know