Doctor Horrible is Philosophy now.

There are probably several people familiar with Doctor Horrible's Sing-Along Blog here, yes? Well now I will bombard it with philosophy! This is actually a paraphrased quote from a friend of mine. You sort of have to appreciate it how Billy sort of warps this idea of "I can't get the girl I want and people make fun of me" into "The world is a mess and I just need to rule it" and have it make sense. Here you've got a character who is just generally down-trodden, and so for his hero he picks Bad Horse, the Thoroughbred of Sin, as a role model because here is a horse who gets what he wants when he wants it without any back-talk--the complete opposite of Billy. Thus he creates the identity of Doctor Horrible and does is best to get the girl and save the day by being a supper villain.
The entire movie basically catalyzes this, and because I don't want to post too major of a spoiler, I'll only post one little song that sort of shows this sort of attitude--In this scene Billy/Doctor Horrible is pulling of a heist that could get him into the Evil League of Evil, headed by Bad Horse himself, but is approached by Penny, his love interest, and has a rather hard time trying to figure out if he wants to pull off his heist and achieve his goal and then get the girl, or get the girl and probably have to sacrifice his dream--what he believes to be for the Good of mankind--him ruling the world.