I think your commentary on the impact of our peer group is spot on. We tend to only work hard enough to compete against our peers.

My assumption is that for a lot of us, we were able to get through school doing hardly any study, yet still achieving top results. The bad work/productivity habits (and that "overinflated sense of your own abilities") were established during this time.

I'm still working on overcoming these bad habits now that I am among smart AND hard working people.