Who are the "socs"? Why do the "Greasers hate them?

From the book "The Outsiders".

The ''Socs'' are the rich kids. They lived on the West Side. The ''Socs'' are always getting drunk and looking for fights with ''greasers''. The ''Greasers'' always thought that the Socs had it better than them, they resented the power and influence the ''Socs'' had because they were wealthy. The ''Greasers'' felt like they were powerless because they were poor.