I have to agree with what you wrote on your blog. The motivation in dependant employment is much worse than if you are doing something for yourself. Back when I was 16, I wrote a full-blown application to facilitate exploiting certain loopholes in telephone switching systems at the time. (Basically, it was a hacking app you could use to make free phone calls.) Complete with documentation, custom user interface, sound i/o, phone book, snazzy design.. a major major project, tens of thousands of lines of code. I cranked out most of it in a space of weeks, working from 9pm until 6am and sleeping until whenever I would wake up, collaborating with other peeps as needed.
Now, after a few years working in "professional" IT, I can tell you something like this would have taken a bunch of guys who are *employed* to create it at least a year. Five of them too. Why? Because they just do their job, their heart's not in it. They will no enough to not look too lazy to collect their paycheck.
It holds true for a lot of areas, not only teaching english.