Yes, the electricity flows on the outside of wire, now add that knowledge to a circuit, and you see that the electricity flows in between the wires. kinda an oval, encompassing both wires.
We are pretty sure that it is resistance that causes light bulbs and heaters to glow. At least we can measure it as ohms. But, what really is that? Why is some material ohmic, and some material non-conductive, and other material super-conductive? That last one is really weird if it is indeed electrons (as particles) running through there.
Trust Britannica to give you all the Modern Materialistic palp.
Yes, i have learned all that shit through years/decades of college.
The phone company runs on 42 volts. They have a giant battery bank.
With a copper bar on one wall for positive, and a copper bar on the other wall for negative, so you cannot touch both at the same time.
One technician had his face melted off because his wire rim glasses fell off his face.
It isn't really volts or amps, it is power potential.
A Tesla coil is a very high voltage, very high frequency transformer.
If all is done correctly, it doesn't hurt at all. It goes around the body.
The problem comes in when you don't get everything in balance, and you get some low frequency stuff going through. And still, it is not usually bad, just irritating. Get good plans and do your best to follow them.