Not an expert, but crazies are everywhere. Breeders have wrought a terrible toll on some (health, behavioral or a combination of both). How many litters of mixed breeding before those "imperfections" go away?
Like with people, I wouldn't include or exclude a dog based on looks alone. Get to know the pupper and make your decision as best you can. If you think that aggression could be an issue after living with the dog then make your decision. If you keep the dog then get proper training for it and yourself & get the right equipment to manage it.