When you have a project bringing in some income, it can be in three states.
It could be growing, and you're happy expanding, solving any bottlenecks there might be.
It could be shrinking, in which case you're trying to put out fires and plug leaks.
It could be stable, so you're constantly on the lookout for ways to get it to grow.
In none of these cases do you get to just forget about the project and just let it live on its own.
For this reason, whenever you have a project that has any traction at all, it ends up taking significant brain cycles. During the day, and especially when you're supposed to be falling asleep, you can't help but think about one of these three issues.
I've had a few of these projects, and I've started seeing the pattern where switching from one state to another never means you get to coast and just forget about it. You might be able to build a money machine (inputs go in, money comes out), but this machine requires constant tweaking. The dream of having a project bringing in income while you sleep is great, but the reality may be that the project is preventing you from sleeping because you can't stop thinking about it.