Well, even if you look at the movies, a hot temper is indicated throughout the Andolini/Corleone line.

In GFII Vito's father is introduced as having been killed because he refused to give in to the local mafia chieftan. Instead of attending his father's funeral, big brother Paolo ran into the hills screaming revenge, so he too was killed.

Gotta give credit to Mama Andolini, who had the guts to bring little Vito to Ciccio in person to plead for his life and then daring to attack him in effect sacrifice her own life to give her son the seconds needed to run away.

Yep...probably in the blood.

Apple