This is the best robot we've ever built. Last year's was a great machine, but didn't really play the game too well (well, in the offeseason it did...). The year before we were clueless (but enthusiastic!) and had no hope of getting anywhere. This year, we were more organized and purposeful in our work than ever before.
As far as what you're describing:
I've been there, I think we all have. But you can take comfort in knowing that you fought the good fight (Unless you didn't, but I'm sure you did...) and everything that robot has or doesn't have is the direct result of your efforts. FIRST hasn't really taught me a great deal technically, but it has taught me a lot about working with other people and the discipline and organization required to work efficiently. So try to look on the bright side, or the ambiguous possibilities of the future!
Failing that, take solace in having come up with a great thread topic.
