For me, I always take the old adage from Ms. Frizzle: "Never say 'Never'!"
I say that because while I've never beaten the two hardest games I've ever played, Touhou 6 and 7, I don't think I can say I'll never beat them. I mean for instance, when I first started playing them I started out as "Ah, crap! How do I get around Cirno's ice vice-grip thing?" And then a month later of playing it, I got to the point where I got Remelia down to the last few pixels on her life bar with no continues before dying... on my last life. I was ridiculously close to beating that game and getting the good ending. Nowadays I don't tend to play the games as often as I used to. Part of it comes from the fact that my interests change, part of it is because the left key on my keyboard is missing, part of it is because it IS a hard genre, and part of it is because I like to enjoy the Touhou material outside of the games as well. But even after all of that, I can't say that I'll never beat the game.
As further evidence to this claim, I can say that a few months ago I tackled Touhou 6 a few times during my stay in New York. And this was the first time I had gone into the game in at least two years. Yet, after all that time (and a few practice rounds), I had an instance in which I got 2nd place on my high score on normal, and another instance where I got Remelia down to her last life bar.
So 1cc-ing Touhou 6 and 7 on normal with Reimu A are on my bucket list.