Not all big dogs are mean. I've always had larger dogs and they've been great, expept Gizmo who my parents have now. He's very aggressive, but he didn't start that until after he was 1yr and we were already attached.
It's not like we wanted a mean dog, it's actually very hard for my mom to deal with him
He's good w/ the family and other dogs, just not strangers. She's thought of putting him down, but my father and I won't let her.