These breeds can be loving, loyal, great dog's but sometimes the strangest things can make them mentally "snap" and eat yours or anothers face.
I remember when I was little, like 4 or 5, my dad's friend had a rot (I think) and he was the best dog ever, according to most reports, until the day that I met this dog and thought it would be fun to role play as Mufasa and growl at him through the glass door. He snapped. He wanted to eat my face off. From what I heard, everytime the dog saw another child he'd snap and go berserk. Not sure what happened to him.