There's so much to do in the world that it makes one wonder why boredom exists.

I've heard this argument before, but it always seemed to me to be kinda misleading. Like, obviously there's a bunch of stuff to do in the world, but when you look at the number of things that it's possible for one to do in a particular moment, with limited financial resources, limited time, and all sorts of other constraints, I think it's totally possible to be bored in the classical sense -- simply because there's nothing to do.

On the other hand, boredom can also be an expression of dissatisfaction, i.e. when one is in the middle of doing something unpleasant (or "boring") but "has to" (quotation marks indicate radical freedom, "has to" here really means something closer to "feels obligated to") keep doing said thing. At that point one can definitely become bored with the task and wish to be able to do something else. And I guess that's sort of the same point: I think boredom arises when the number of things one can do is constrained past a certain threshold.

So I think it's also misleading to construe all boredom as related to indecision.