What is something that, no matter what context it occurs, makes you doubt people?

I don't believe that I will ever completely doubt people. When we lose faith that people can do good. Where will we be? My goal is to surround myself with those who are trustworthy, honest and share the same values and belief system that I have. One thing though that I have been working on is forgiveness. I try not to be so hard on people, knowing that I am imperfect and make mistakes all the time. It has helped me to meditate on why we do the things we do to cause others to doubt  and work from there