I mean, I think there is an agreed upon phenomenon that the more effort you put into something, the more you end up appreciating it. See, e.g., the Ikea Effect [0] and The Little Prince [1].
But I also think there's something that makes harder things more compelling to certain people. I'd be speculating to apply this to you, so let's take me for example. I've caught myself wanting to take the harder route or do the thing that is perceived to be more challenging, just to prove to myself that I can, and then to tell others about it, and not because it's inherently more appealing. I'll take the longer hiking path, I'll bike in a higher gear, I'll go backpack alone in South America over Europe, etc.
Because there might be something lingering underneath it all, a fear or insecurity, maybe a voice from a teacher or parents years ago, that says I can't, so I want to disprove it.
Also let me suggest something - by choosing the harder thing, you somehow have more latitude to fail. Didn't master classical guitar this year? Yeah that's understandable, because that'd be really difficult and most people can't. But if you choose something "easier" - like you didn't master a simple song on the piano - your sense of self worth might be more easily threatened.
[0] https://en.wikipedia.org/wiki/IKEA_effect
[1] This quote in particular sums up the point: "It is the time you have lost for your rose that makes your rose so important."