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. It's is also the reason most people look painfully average. See conformist.
A term referring to the ability to accept, or to be able to tolerate, differences and diversity in other people or groups of people. Tolerance. Some opposite notions of social acceptance would include racism, sexism, homophobism, and prejudice in general.
"The highest result of education is tolerance." -Helen Keller
Learning about other races and cultures promotes social acceptance.