Friendships are the relationships based on mutual trust acceptance and common interests or values.
People look to their friends for honest reactions, encouragement during bad times and understanding when they make mistakes.
Most teens think that it is important to be part of one or more groups of friends. Interacting with others helps you to build self- esteem and to learn about yourself. 
Types of Friendships:
Some friendships are casual and some are close. Some are even with the opposite sex.
Casual friends- often occur because people go to the same school, live in the same area or have the same interest at heart. Short-term, casual friendships offer the chance to have fun, to try new things and to learn to get along with a variety of people. These friendships may remain casual, or they may develop deeper, long-lasting friendships over time.
Close friends-close friendships with other who share similar goals, values, or interests. People are drawn to others whose personalities complement their own. Friends may have some positive qualities that are the most important building blocks of a relationship such as this which includes:
  * Loyalty
  * Honesty 
  * Empathy
  * Reliability
Friends of the opposite sex- opposite –gender friendships develop more often now than in earlier generations because if changes in the gender roles. Gender roles are the behaviors and attitudes that are socially accepted as either masculine or feminine. Gender roles vary from culture to culture. In the United States gender roles are less rigid today that they have been in the past. Many people now choose activities and behave in ways traditionally were reserved for members of the other gender. Bothe male and female learns to express various emotions including tenderness and assertiveness. They let events or situations dictate which emotion is appropriate.