Factorio completely hacks and breaks the brain's reward system of anyone interested in problem solving. It's a never ending, deep, wide, and task oriented rabbit hole where you can create very personal solutions that are very rewarding.

And the scale is massive, from simple obvious problems at the start, to huge, factory wide ones that emerge from the solutions you implemented before, that require carefully planing and phased execution to avoid breaking things.

And then you discover the circuit network, and the complexity of the solution space available to you suddenly becomes exponential.