I love the section where Atticus takes out the old dog, it is amazing to see the way that Scout thinks so little of him at the beginning of the chapter. He doesn't "drive a dump truck," he isn't "the sherriff," he just works in an office and goes about his business. He isn't tough or dangerous or really much of anything that Scout could brag about.
Then old Tim Johnson (yeah that was the name of the dog) gets rabies and decides to put Atticus' children in danger. Atticus raises a rifle and puts a round through the dog's head from quite a distance and without any hesitation.
Suddenly Scout learns that her father is a "dead shot" and perhaps he isn't quite such a weenie after all.