While it is true you can choose the people you want to be around, you can't always choose the people you have to be around. Many I find, much to my disdain, lie. Straight up bold face lie through their very teeth. I will tell you something about that, some of these people are very good, very believable and seemingly sincere. For this reason I find I am often on guard and seldom just accept things I am told as the truth.
With that being said, I do not automatically assume all things are lies. Instead I just take things at face value and have faith that those that do lie will be exposed. If I have learned anything at all from dealing with large numbers of people, it is usually a good idea to never repeat anything anyone else ever tells you unless you are 100% certain it is fact, least you be the one propagating rumor and mistrust. Keep your opinion to yourself and your closest confidants and never let on what you think or feel about another person unless you are telling it right to their very face. It keeps drama out and makes it easier to find those that are kindred.