wow, that Bayles quote... almost shakes a part of me up. GOLD.
(I read that book a long time ago. might be worth a reread.)

re: finishing projects... sometimes not all are meant to be finished. sometimes the project isn't the point - just a step in the process of skills development, each miniature success & failure within each the piece of a much larger puzzle - each incompletion, itself a completion towards future compositions yet to come - more of themselves which may also be incomplete, and a few completed ones developing into masterpieces, that never would have been possible with the trail of 'incomplete' pieces behind them...

the FIRST piece of feedback that came when opening this post, however:

a distinction in the headline wording, "what do we want to get out of..."

the major difference that will unlock success for most people is a refocus of the question - shifting thinking from what we want to get, to what can we give...

the giving piece has to come first.

for the rewards, of course. but also for the personal satisfaction - giving our creativity, pouring our hearts out, contributing, serving, supporting, and investing in the community... THAT'S the path to getting what we truly want out of it all... ;-)