Social acceptance is the fact that most people, in order to fit in with the others, look and act like them. It stops (mostly) everyone from truly being themselves.

Quoted from an article:
COLUMBUS, Ohio - What others think about you may affect your own health and well being. A new study found that college students held in high esteem by their roommates were happier and had less physical problems than those who were not liked as much.
The less-favored students had more mental and physical problems, such as low-self esteem, depression and illness.
"According to this study, social acceptance affects mental and physical health more than health predicts social acceptance."
And while researchers in the past have acknowledged that a link exists between social acceptance and personal health, the jury was out on how the two affected each other. According to this study, social acceptance affects mental and physical health more than health predicts social acceptance.

http://researchnews.osu.edu/archive/esteem.htm for the full article.