Realizing how fucked up life is was a gradual process for me. If I were to try to pinpoint where it began, I guess I'd say around when I was 13 or so, and read a detailed account of the Donner Party.
In case anyone's not aware, the Donner Party were a group of settlers back during the days of the Oregon Trail. They ended up getting snowbound while attempting to take a shortcut through the mountains. Long story short, they didn't have nearly enough food to make it through the winter, and resorted to cannibalism.
I found it pretty disturbing, especially the description of an infant clinging to the half-eaten corpse of its mother, and it (along with other things) caused me to question a lot of my beliefs at the time. What really hit home was the realization that they weren't bad people per se. Civilization's just a thin veneer, and once they began starving, the animal instinct took over.
I'd always been taught as long as you were truly a good person, or your devotion to God was strong enough, you'd be able to avoid doing sinful things through sheer willpower. This kind of shattered that belief. I realized it didn't matter how "good" someone was, under the right circumstances, anyone could be pushed to do anything, myself included. I hated, and still hate, knowing that.
I'm sorry, this is kind of just a stupid childhood memory.
