Ben Casnocha wonders why many some individuals don't work hard:
Here's a non-obvious reason: working hard is risky. If you work hard and fail, you don't enjoy the self-protection that less than 100% effort affords. If you get a C on a test in school, and you didn't study much, then it's no big deal -- you just didn't study enough. If you get a C on a test in school, and you studied really hard for it, then you must just be dumb.