Thanks, this is a thing I was confused about, and now it seems so obvious in hindsight!
Yes, there are hundred brilliant ways how I could spend my day; so much better than my current habits. But they are hidden among the billion possible ways to spend my day, and most of them are not better than what I have now. (Further complicated by the fact that some things require many days of doing the right thing before the awesome effects manifest.)
If you keep introducing random changes in your life, you increase the chance you may randomly find one of those treasures (see The Luck Factor by Richard Wiseman). But that's not the same as deciding "I am going to choose a better option right now".
Naively, for instance from the perspective of me as a child, it seems like a person has vastly many possible options at each moment, leading out in every direction, where many of them surely lead to amazing things, and thus it should be very easy to have an incredibly great life and make a huge positive difference to the world.
The problem with this is that having the ability to do incredible things, and wanting to do those incredible things, is not enough. If you can also do a bazillion other non-incredible things, then you also have to be able to pick out the incredible path from among the rest, and even if you do, a moment later it hits another incomprehensibly complicated intersection of unmarked paths, and you have to do it again.
This perhaps sounds obvious, but I think we do often still talk as if what happens is determined by people’s goals and their capabilities, and ignore the issue of computing which exercise of capabilities will bring about which goals, or leaving it as hopefully irrelevant noise in the model. My tentative guess is that this is a real impediment to thinking about the world and strategizing about life well.
I don’t know if anyone has a better model, or has thought about how bad this is. My tentative guess is that it is bad. It seems like something economists would think about, but I’m not sure what it would be called.