I've always wondered about the uncertainty boundary between classical and quantum physics. More recently I've been thinking about how the difference between the narratives we're fed and the real world and how a similar uncertainty boundary exists between them. The narratives are a "good enough" approximation of the real world for the average person to make it by, but they can't accurately account for every situation.
Then I read ideas about the physical universe being fake, and I wonder if the quantum world is "more real" than the familiar classical world. It also makes me wonder about our minds, which also operate at the quantum level.