Bully (go to number 5)

A European study in 2009 found that children who bully at school are likely to also bully their siblings at home. That led a researcher involved in the study to speculate that bullying behavior often starts at home.

"It is not possible to tell from our study which behavior comes first, but it is likely that if children behave in a certain way at home, bullying a sibling for instance, if this behavior goes unchecked they may take this behavior into school," said Ersilia Menesini of the Universita’ degli Studi di Firenze, Italy.

At the office once bulling gets started it tends to get worse.

"Bullying, by definition, is escalatory. This is one of the reasons it’s so difficult to prevent it, because it usually starts in really small ways,” says Sarah Tracy, director of the Project for Wellness and Work-Life at Arizona State University. [emphasis mine]

I always hated it when other kids took something of mine and tossed it back and forth, taunting. This kind of behavior among siblings is probably the first stop to violent bullying.