"...all that effort, for NOTHING" can be an easy belief to fall into, but it really wasn't for nothing. If you think about the work you put in before this point in time as a sunk cost, and look at it as "well, where can I start this problem from now?" you'll see that your starting point is a WHOLE lot different. You find yourself with a much more informed opinion from which to climb up from.
For me, the hard part is that an experiment can be a lot of work... all that effort, for NOTHING. :(
Though Tesla has more geek cred these days, Edison also did some stuff. He said: (http://en.wikiquote.org/wiki/Thomas_Edison)