If the question is "given all other possible uses of my time, is this one the best use possible?", then the answer will be "no" for almost any given value of "t

If the question is "given all other possible uses of my time, is this one the best use possible?", then the answer will be "no" for almost any given value of "this". A likely result is doing nothing while one waits for the "perfect" thing to do - it might not apply as much to people on news.yc, but this does describe many people I know. If the question is "given all the ideas I have right now, and considering the effort to implement each, should I work on this?", the answer might be different.