Your past could effect your future
Some people say that when you went through something tough it's over, get over it. Yes eventually you do move on but could you really ever forget what happened to you?
If you lost your trust in someone it can effect your future. If you had a lot of friends betray you, you might think every friend you make in the future will be bad. It will leave you feeling insecure and worry about things that you really shouldn't worry about.
Yes there are a lot of people you can't trust but trust is important in a friendship or relationship. If you can't trust someone, then you shouldn't be with them. Some people scar us but we must remember there are good people in this world.