Seconded. Obviously you don't want to work on crap, but keep in mind that Google was supposed by many to fail based on the existing maturity of the search market:
http://www.bvp.com/Portfolio/AntiPortfolio.aspx
Some of the ideas you've tossed aside were wins.
For that matter, just start writing down every idea you have, whether you think it's good or not. Keep track of your batting average. Keep track of the kinds of things you were right on. Obviously a long-term trending thing, but probably useful at some point in your future.
From my experience writing every single new ideas down really helped have more ideas and better ones too...
I feel that just the act of writing them down forces you to think more about finding great ideas...
Some of the ideas you've tossed aside were wins.
For that matter, just start writing down every idea you have, whether you think it's good or not. Keep track of your batting average. Keep track of the kinds of things you were right on. Obviously a long-term trending thing, but probably useful at some point in your future.