We humans are social animals. 

Social interactions are essential to maintaining a sense of belonging and allow us to engage more fully with our feelings and emotions.

So, when we get sidelined, or cut out of the group, it can hurt. 

It can hurt a lot.

But being ostracised is more than that and it can have a terrible psychological and emotional effect on us, so why do we do it to others and what function does it serve?

Dr. Kip Williams, Distinguished Professor of Psychological Sciences from Purdue University