Disposition? Didn't cry when my grandparent(s) died, i make little effort to be with friends and family, i alternate between inferiority and superiority complexes, depends on my age. Hate my culture, but can't assimilate into prototypical America because of racism, so I'm stuck in this middle ground where I don't connect with anyone (and consequently, Americans call me white-washed and my family says I don't know where I came from).
Divorce, poverty squashing all my interests (sports, martial arts, music, no money to support any of those things), lack of social life/jobs/transportation due to age, bullying in middle school due to age, general bad parenting (I have little respect for my parents, so they must have done something wrong).
They pushed me into the whole age thing. People will tell you it's nice to have a headstart, but it doesn't justify 12 years of misery. The age gap between me and my peers were such that I was too old to be pitied/looked after, but too young to fit in, so I just got shat on.
The good thing is, now that I'm an adult, I can make decisions for myself and find some passions, like music and dancing, probably the two things that have stopped me from becoming depressed.