All Joking Aside

I have always wondered why people feel the need to mock others? Mimic I get, people do some rather amusing things and copying allows a reliving of the moment. But to Mock? I know it is a power play, maybe that is why. Could it be that the person doing the mocking felt that they had lost control of something important and the only way to attempt to regain control is thru belittling the person they lost control to?