Honestly, Jack, I'm not exactly sure what it is you are asking here. What's the 'needle in the haystack?' Meaning? Satisfaction?
If your last sentence means that possibly futile activity may be preferable to abject surrender, I suppose I agree, more or less; one of my watchwords is "despair is not adaptive," and I frequently remind myself that "there are *always* cards to play"--though the latter I'm prone to doubt at times.
But "ghost and lost causes?" I try to be selective enough to work on something that has at least a prayer.