I could be wrong here -- I haven't exactly done a long-term study on this -- but my impression is that the way young people are treated (in the US at least) sets people up for this. When you wake up is dictated. What you do with most of your waking hours is decided for you, without your input or slightest consideration. What you wear, what you're allowed to say, who you spend your (increasingly limited) time with and what you spend it doing and where, even the emotions you express on your face, can be dictated to you by others who consider themselves in the right to do so.

This continues from before you are self-aware until nearly a decade beyond the age of abstract reasoning.

By the time you're allowed to make a serious decision, others have been dictating them to you for your entire conscious life. It's no wonder people never learn how to decide for themselves. I'm reminded of Brooks from The Shawshank Redemption: institutionalized. So conditioned to having no freedom that it's terrifying rather than liberating when you finally do.