Working with Chess Mentor is a bit like being in a relationship. Grind out the challenges knowing full well that being right is worth a point and being wrong may cost you nineteen.
And even if you nail it every time, there's nobody to impress. No certificates or confetti canons when you complete a course, just the next problem to solve. And banging out a course may not necessarily even make you win your next game.
You have to take the long view. It's study, practice, repeat.
It's not misery, though. (And if it is, are you sure chess is really your game?)
You get the cool feeling of those "Aha!" moments, when something makes sense for the first time. And the process gradually inculcates chess virtues that lead to more satisfying and successful play.
But it takes a minute. :)