I'm stuck thinking about this situation. I imagine that there are two oppositely charged objects at short distance $r$, put inside an insulator (Can I say air?). They generate a net elctric field, but since they're apart there's no electrons flowing. Then I connect them with a bizzare conductive wire and electrons start flowing till balance is reached.
How and why the electron flow will follow the shape of the wire?
Is it beacause the net electric field?
Can we say that they prefer to follow a strange path through a conductor than a straighter ,shorter one thorugh an insulator?
I tried to make a picture of the situation I describe. Since for my understanding it's easier to picture electrons flowing, I drew a reverse electric field so that charge will move from low to to high potential (hope I can do that!).
I hope it doesn't seem a too awkward question. If there is any problem with this question please make a comment and I will try to edit it. If there's any problem you want address don't hesitate.