non-technical understanding of current flow behavior
See other questions on the basics e.g. Is voltage the speed of electrons?

For understanding current, it's much easier to forget the electrons and stick with the conventional model. The other important thing to understand about current is that it's not exactly like water - it doesn't set off into the circuit and then "decide" where to go. Current is more like a bicycle chain: there has to be a complete loop for it to move.

So how does it know whether there's a complete loop or not? This is where the voltage is important. Voltage represents a level of energy in the electric field between two points. The field inside a conductor "wants" to flatten out so the level is the same everywhere.  So if you attach a conductor to a battery terminal at one end, the other end will acquire the same potential.

What happens when two fields of different potential meet? That is when a current starts to flow, as the fields attempt to equalise potential. You get an electrical wave propagating out from where the switch closed to make the circuit complete.

The waves travel at a high fraction of the speed of light. This isn't relevant to little circuits with batteries and lightbulbs, but it is very relevant when you're trying to use switching to send digital information.

(This discussion does not account for superconductors or semiconductors. It doesn't address the capacitor either, but what a capacitor does is store energy through changes in electrical field strength. It does not store current; it can be said to store voltage, but the energy associated with that voltage is what's important.)