I don't know, I'm making this up as I go.
Sorry for the second Adam Savage related post, but I thought this one was interesting. Early working as a consultant I found myself saying yes to a project just for a paycheck (or to show my parents why I didn't need to stay in college) even though I really couldn't do what the client is asking for; but I would get the project done.
One time I got a really simple project from a new client, the project was so simple and I had so much school work the project got pushed to two night before it was due (which was the same day as an exam). They were using a custom web framework with no documentation or even comments in the source code and I couldn't finish on time. Around 6:45 am i left for school with the project unfinished. I got to school around 7:00 am took my exam finished by 10:00 am and went to the library to write an email to the project manager and tell him I couldn't finish and I was sorry. While instead of doing the write thing I went home and fell asleep and didn't wake up till 9:00 pm. Where in my email inbox was an email from my project manager which wasn't really good, but I dissevered every word in that email.
Since then I stop taking project I didn't have the time to finish. But this situation taught me two really important thing about myself: one I will always fail horribly at some point and two I will always learn from the horrible failures.
Failure is always an option.