As I said, pits get a bad rap. The uneducated seem to advance the totally wrong concept that pits are bad dogs. I was raised around many different breeds of protection and combat dogs my entire life. Including but not limited to, American Pitbull Terrier, German Shepherds, Rottweilers, Doberman Pinschers, and Great Danes. Of all of those breeds, my dads pits were probably the most playful and sweetest tempered. Their protective instincts were not to be trifled with in any manner nor would any of our other dogs. Basically, you messed with one of the kids or my parents, you would be on the bad side of some serious teeth. The most ill tempered dog I have ever seen in my life was one of my dads old coon hounds. A big old Red Bone. I swear that dog didn't even like itself. The only person that dog would pay any attention to whatsoever was the old man. It would even growl at him sometimes. The old man would growl back and that usually ended the conversation. The old man loved that old dog. Even shed a few tears when it died. He said, meanest sob on the planet but not a more dedicated coon hound has ever lived.
Like MountainDevil54 and BarnesAddict both said, it is all in the training and raising of a dog. That would be any dog. Some aggressiveness of course is genetic and relative to the breed just as hunting instincts or herding instincts are in others. But a dogs temperament all has to do with it's health, training, and relationship with it's owner. To put it as simple as possible, a bad dog is 99 percent of the time the fault of a bad owner.