Any breed of dog can turn on it's owner. Whether it's a pit bull or a feist. Of course there are more aggressive breeds than others. However, no one has ever linked any action or common thing to dogs turning on people. This could happen due to age or a psychological problem with the dog. I hope this helps you to realize that it's not just aggressive dog breeds who turn on their owners. However, if you're planning on adopting a pet you should truly study up on that breed before you adopt to make sure that you and your pet will be happy. Adopt responsibly!!
A dog is a product of it's environment. If a certain breed intimidates you then just cross that breed right off your list. But chances are the dog your interested in will not turn on you - unless there is a neurological issue with the dog, it will not just snap. If a dog is properly socialized from a young age and has proper obedience training you will not have an issue!