This might not work.

I thought it was going to, I really did. 
I thought this was finally the answer I have been looking for.
I thought it was going to be the next big thing.
I wanted it to work out.
I wanted it to be important, to make a difference.
This was going to change everything.
All the facts lined up, the data was there.  It was rationale, coherent.
It just made sense.

Was it the idea that was flawed? Our expectations? Our effort?
When we failed, was the game really over or was it just getting started?

Fear usually has a pretty good story to tell.  So does doubt.

Stick to the practice.