When people go back on their words, its a sign of no accountability, on their part. There is nothing worse than making a commitment, only to be drop it, and not care of the consquences. In my nature, I say what I mean to say. If I back track, I still do it, to maintain integrity. Honesty is my policy.
Losing the meaning of your words could destroy relationships, friends, and worst of all trust. Words without meaning is a weapon, people use all too often, to set traps for their own advantage. This works great in the short term, you may pick up hundreds of friends. To the con artist, they have a difficult time, keeping a deep relationship because their weapon gets too much in the way.