This might seem obvious when put like this. It might be really obvious to most people already. But it hasn't been clear to me until recently.
I've been lucky that for large portions of my life when I've set out to do things that were the most interesting to me, I benefited substantially. I learned a lot, I got jobs, I made friends. It's been a good time.
But the strategy of "seek out interesting; profit" doesn't work forever. What's interesting isn't always what is most important. Actually, I think it rarely is... Often times the most important things for me to do at a particular time are quite boring, difficult, or challenging.
And I think it's better to do what's most important vs what's most interesting. Isn't that the definition of important?
This doesn't mean I won't learn or do interesting things in my life. I will, but I imagine most of the time they will come up on the side rather than being the main thing. And I imagine often I'll decide that, for that period of time, I really do value learning something interesting. In which case, it would then be the most important thing!