Telling others about your goals forces you to accomplish your goals.
Telling your support system like your family and friends about your personal goals will inspire someone to complete their goal. Having the support system set up is a motivating tool to succeed. For instance, a person wants to quit smoking so said person tells family and friends that quitting is a goal with a set date. The support system that was informed of the goal will most likely remind that person that quitting is a goal whenever they see that person smoking. Without telling anyone about the goal it would be very easy to just forget it and not feel any guilt for failing. With the support system in place that person will feel a greater satisfaction for completing it by a receiving appraise from them.