If a weak dog, or person, 'drives you up the wall' (in your own words) and makes you want to kick it, then it shows that bullies are even weaker. For someone to want to hit or kick a 'weak' dog, it shows that the person doing the kicking is actually even weaker than the 'weak dog'. Bullying weak things shows that the bully is scared of most things, including their own selves, and is in a very unhappy place indeed.
Someone once said that violence is the last resort of a frustrated mind: I agree in part, though not completely. I'm not making excuses for the girl, who was probably a horribl