Friends affect the ways that you think and feel about yourself. How your friends think about and respond to you will, over time, have a strong influence on your perceptions of yourself. Back in 1999, a group of researchers found what they called the Michelangelo effect. That is, when you are coupled with a partner who sees you, already, as the kind of person that you would like to become, the relationship will have a positive influence on you because it helps you become more like your ideal self. You can also expect a similar effect from close friends. However, friends who treat you less favorably will likely have a negative effect on who you become. So keep this in mind; choose your partner and friends wisely.