Many times, individuals fail to understand the life experiences of twins. As onlookers into the lives of twins, other individuals don't realize the implications of constantly being compared to another individual. Comments such as, “You must be the evil twin? Who is smarter? Who is finer? Who is nicer? Where is your other half?” eventually become a nuisance and embarrassment for twins. Some twins purposely avoid being seen together in public to avoid such embarrassment and many twins really resent being entertainment for other people.

By adolescence, many twins have reached a level of maturity and individuality that provides for them to actively seek out different interests, friends and romantic partners. Twins recognize that they have distinct identities as twins, but they also recognize that their own identities as individuals are distinct and separate from their twin identities. Onlookers fail to recognize that twins have this dual identity - that as a twin and that as an individual. They long to express this individual identity and they want to be seen and treated as individuals.

By the time they reach young adulthood, twins will begin to live separate lives and they need to begin to established separate identities outside of the twinship during adolescence. Even though they tend to continue to keep in close contact with one another, maturity provides many more separate experiences, which allow them to then develop even more distinct lifestyles that they may share with each other in conversation rather than directly. 

Research shows that adolescent twins remain closer to their parents than singleton children and that often times, they find it hard to reject their parents' values especially if the other twin has also reinforced those values throughout childhood. Two studies done in Finland found that twins used alcohol and smoked less often than their singleton counterparts. The research included and tracked the progress of 284 twins from pregnancy through adolescence. It concluded that the twin bond offered the support that these teens needed to say "no" to dangerous behavior.

Multiples, which form a peer group unto themselves, may find it even easier to reject the questionable values of others. In addition, the twins in the study were found to be more physically active than their singleton counterparts, participating in sports more often.

Every teen seeks someone to talk to and to confide in. While singletons are more likely to turn to a close friend for this kind of support, most twins have that special relationship that allows them to be each other's confidant. This is the one positive component of the twin bond that helps to ease the many teenage growing pains as well as  some of the other special challenges of being an adolescent twin.

A twin's pool of friends is usually larger than that of singletons. Studies indicate that being a preteen twin may actually boost a twin's popularity. One study of more than 1,874 eleven- and twelve-year-old twins and non-twin classmates used a "peer nomination technique" to decide who in their classroom displayed socially active behavior, which included strong leadership abilities, being outgoing and popular, compliant behavior and the ability to control emotions. The twins surpassed singletons in nominations and male-female twins exhibited stronger socially active behavior than singletons.

References
http://drbarbaraklein.squarespace.com/not-all-twins-are-alike/

http://multiples.about.com/od/twinsinschool/a/teenagetwin.htm