[zfnmxt]

In many ways I agree with your opening sentence---maybe I shouldn't have written "fun". I think I was trying to get at something more like that the experience of learning itself is itself a good thing (even if it's not fun, even if it's suffering, even if it's hard) and I think mechanical and stoic recipes to optimize the process fail to adequately appreciate that fact.

The best part of learning piano isn't getting good at piano---it's learning piano. And sure there are some things we have to learn that we aren't that interested in learning, but I think even those things have the capacity to be worthwhile experiences if properly framed.

I think applying the word "efficient" to this area is suggestive of urgency and greater purpose---I don't buy into either.

[jackphilson]

I think 'fun' is a prerequisite for optimal learning, you can definitely have both.

And I think greater purpose is definitely a thing if you subscribe to a utilitarian moral framework

[proper_elb]

I think 'joy' would be a fitting term, perhaps? Here (https://www.1517.org/articles/cs-lewis-on-joy) C.S.Lewis defines it well, and distinguishes it from 'pleasure' and 'happiness'.