Now here's an interesting idea: Why some people learn faster.
Though the article is primarily focused on why some people are more inclined to learn new things and thus learn things faster, it raises interesting points that may explain a lot about grad school, academia, and post-ac angst.
The research shows that if you praise a child for hir effort, ze feels that trying is all ze needs to do for praise and ze is willing to try harder puzzles. He or she is willing to risk failure. However, if you praise a child for hir intelligence (for being smart), ze feels that ze needs to show ze is smart to get more praise and ze is NOT willing to do harder puzzles. He or she is unwilling to risk failure.
So let's follow this bit of psychology through grad school. Most grad students go to grad school often partly, if not entirely, because they've been told they're smart and that's what smart people do. Follow the train above. These students are less likely to risk failure. This may explain a lot of the redundant research in many fields. Yes, I know science happens in small steps but there are small steps and then there's spinning in a circle and until you fall down. You know of both types in your field, whatever your field may be.
Anyway, these students are given one career path: professorship. They do less than groundbreaking research which they know is unlikely to fail. They get articles published and go on to become professors. By the time they join the professoriate, or adjuncthood (which ain't the same thing - google it), they've had this risk aversion strategy reinforced throughout their entire grad school career. It shouldn't be shocking if they then go on to reinforce this strategy with their own grad students. To be fair, I think some level of risk aversion is essential for an academic career. Sudden movements scare people - the kind of people who may be voting on your tenure.
This idea also explains the angst of the post-ac transition. Post-academics have also gone through this system and had their risk aversion system reinforced. However, in order to change careers, you must be willing to take risk. So, post-acs need to change from risk aversion to risk seeking. You've got to go out on a limb to change your path and that's scary. Grad school does not engender such feelings. This risk aversion is also one of the stereotypical traits business people have of academics. As a result, not only do post-acs have to become more risk seeking, they have to be so comfortable with that idea that they can sell it to a prospective employer. Yeah, that could cause a bit of angst.
So, ask all your friends to praise your effort to change your life and not your intelligence for leaving academia. Maybe it'll make you braver!