> why would I retain any information I didn't genuinely want to know
First things first, stop assuming you know what you want, or that useful things are immediately obvious. Just play around damn it, all the time. Fiddle with it. Fool around!
> Even if I was fooling around with, say …
This static object may or may not be interesting. The tools and techniques are more so. See things you would do differently? That’s useful. See things you hadn’t considered? More so. When I fool around with objects I learn that good finishing has layers and layers of interfacing between the objects themselves and how they fit or are used (like a grip or a fastener or way of attaching that makes assembly easier, etc.)
> doesn't necessarily make me care
I guess that’s why you’re having trouble with this whole curious thing.
If you find something interesting BY ACCIDENT, then you learn something. Destroy your boring expectations. Even if you don’t think it’s important now, just having gone over it reinforces your familiarity. Handling an object makes you familiar with the weight and feel. Later if you handle a fake, you will remember it doesn’t exactly feel right even though at the time those details were uninteresting.
Curiosity is learning by accident as much as anything. And it’s a big mistake of yours to think you will be immediately aware of everything useful later. Those thoughts you have in the back of your mind days, weeks, or even years later are the slow revelation that curiosity provokes.
When you stop being curious, you become stagnant in your knowledge, and that is very boring of you.
Talk to others about the non-obvious things your curiosity experiments reveal. I think you’ll find socializing about curiosity very gratifying in itself!