Why do we, as a species, chase what is difficult? It seems as though difficult is not enough to discourage us and we don't understand impossible enough that we are unwilling to attempt to convert it into the ordinary. I'm not talking about the special few geniuses among us, the mavericks, the freaks of nature. I'm talking about that never say die attitude which applies to us all, albeit at varying degrees; we are all willing to push the envelope when we care enough about X.
It is the root of the no pain, no gain policy.
Take rock climbing, for example. It is the only reason I'm even writing about this. It takes a no pain, no gain attitude to stand at the bottom of a sheer rock face looking up at an invisible crest and think to yourself, "I'm going to climb this." Why? It is absolute lunacy.
But, of course, it is too easy to dismiss it as a lunatic's whim, even if the aforementioned gain is of little practical value. Even if you can't brag about it to anyone, because nobody really cares, and even if you don't derive any material value out of it -unless you value scrapes and bruises, and maybe a free-falling death .
But it means something.
Just like everything else that that drives us to transcend our (assumed) capacity in order to achieve the impossible, we are forever impelled by rewards whose value cannot be ascribed by anybody but ourselves. There is only one secret to 'making impossible happen'.
You are the secret.