@nixCraft Reminds me of the time, when I tried to learn Ruby + RoR. I would get up to some point in the tutorial, then error, then searching around for clues how to solve the error, getting a bit further, but ultimately my state and the state in the tutorials diverged and I could scrap it all again.
I guess 2 reasons: Unstable APIs and lack of understanding of what happens behind the scenes, so that one cannot fix it oneself.