They will grab your pants legs as you walk by in their teeth. They will jump up and grab your sleeve. They will come running up to you, jump into your lap, and whip their little heads around in joy with their mouths open, sometimes clipping you with the exposed teeth. You don't want to hit your puppy, but you do need to train it. Your obedience trainer will be of great help in giving you guidance on this.
Most dogs love open doors.
The moment they see one, they head for it at full gallop. By the time you realize there has been an escape, the dog is normally quite a good distance away from the house, down the street. We teach all our kids that when we go to a door, no matter what door it is in the house, they are to back up, sit, and stay. When we reach for the doorknob, if the kid begins moving for the door again, we leave the door closed and start all over again. Eventually the dog will be trained not to run for the door when it is opened.