I just find that I cannot enjoy something if I have too much doubts. I may enjoy doing it once or twice, but if I'm constantly caught in failure/exhaustion, it's no longer fun.

I used to be into composing and improvisation, but each time I attempt at it, the result was to "meh". I walked the keyboard but knew nowhere to go. The fun was basically an initial passion plus a little curiosity, which in me, tends to die quickly if no fuel is supplied.

Meanwhile, my friend who actually studied Jazz, can sit in front of a piano and just play, fully enjoying every second of it, while entertaining everyone else. Comparing with my randomly walking on the keyboard, it's a higher level of fun as he attempts to weave the harmonies and melodies, and it's more lasting and more complex.

Again, it's a quite personal thing, as I also have a friend who literally doesn't do anything new. He neither dabbles nor learn seriously; has no hobbies apart from having dinner with friends; but still, he seems to be really happy.