In my case, it was 8 years of my good work. And, 30 of my employees, who are now in a very different situation. (I'm contractually prohibited from discussing the matter, so you'll understand my being a bit oblique.)
In answer to your last question: no, it's not that that one project was really more important than anything else I could ever do; but it took a few years to get past the bitterness to be able to focus, and find the right "next step"-- which could have been avoided, if I had sold to the right people at the right time (instead of the wrong people at the wrong time).
So: "selling out" can be a great thing, if done well. Or, a really soul-searing thing, if done poorly. Choose wisely. Here endeth the lesson.
In answer to your last question: no, it's not that that one project was really more important than anything else I could ever do; but it took a few years to get past the bitterness to be able to focus, and find the right "next step"-- which could have been avoided, if I had sold to the right people at the right time (instead of the wrong people at the wrong time).
So: "selling out" can be a great thing, if done well. Or, a really soul-searing thing, if done poorly. Choose wisely. Here endeth the lesson.