Friendship is a source of joy, togetherness and security. We are social beings. Harmonic relationships with others helps us find our place in the social world.
During our teens we often orientate away from the family and out into the world. Friendships become more important. We look for our own identity, and seek people and "things" that will support us and create a sense of belonging. To be excepted is important, to be excluded can be extremely tough.