Feeling useful is important in anyone's life, because it makes you feel important: like you matter. Usually, that kind of usefulness is something you seek out in a school or career context. But today, why not explore how you can be socially useful? Help people make party plans, decorate an event room or put together an invitation list. Heck, volunteer to be the designated driver. Any of these will be great ways to show how you matter (in a social context) to your friends.