How do you overcome resentment?

Overcoming resentment is not an instant thing. However, you can forgive what happened. If you were not given that job, invited to that party, or were snubbed, the reason may not be anything you could have controlled. Rather, you can look at it as just not being the right thing for you at that time. Other chances will come to you. This does not mean that you have to forget the treatment, but that you will be better off if you reframe the experience and move on. If possible, reduce your commitment to those who mistreated you.