When I was small, I stayed at my grandparents house most weekends and something that has always stuck in my mind was : my grandfather drinking and getting angry with my grandmother. He picked up (what seem to be the biggest ashtray) and threw it at her.
I remember screaming at him and punching him for it but you know I never saw him do it again.
Now maybe thats why I continued to stay at there at weekends, who knows!