All people operate from the same two motivations: to fulfill their desires and to escape their suffering.

No matter what kind of behavior other people exhibit, they are acting in the most effective way they are capable of (at that moment) to fulfill a desire or to relieve their suffering. 

These are motives we can all understand; we only vary in method, and the methods each of us has at our disposal depend on our upbringing and our experiences in life, as well as our state of consciousness. 

Some methods are skillful and helpful to others, others are unskillful and destructive, and almost all destructive behavior is unconscious.