I'm a bright person, and I learned to program in 6 months with only "programming" experience being Excel VBA scripts.

Joel's method would have made me drop out and convinced me that programming was terribly boring-- much like a how a kid who wants to play the piano would feel after starting out on 6-months of only scales.

I learned so quickly because I loved it, and I loved it because I could be instantly productive making apps with Ruby on Rails. There was still a lot to learn, but those things could be learned later "in the field" as they were relevant.