I just want to know what happens to all the electricity when it comes to the end of the wire?
If the end of the wire is "open circuit", nothing plugged in, and nothing is used. It wouldn't go through, the electrons (to be exact, the current) will stay where the source is like the coolant inside your engine not flowing through your radiator if the thermostat is closed off. Just like water is not used if the faucet is not turned on, electricity is not used and stay at the transformer if it is not used (assuming some loss due to efficiency).
Think of it this way: You have a generator connected to the transformer to your house. If you are not using electricity at your house, the voltage in your house is the same as the voltage at the transformer with nothing being used or transferred. The transformer is taking in electricity as input to transform to the output side electricity, but there's some loss as heat at the transformer (say 10%), and that transformer would take electricity from the generator and make that generator be harder to turn by the power source (steam, gas turbine, water wheel, etc).
The more electricity you and your neighbors use, the more it will draw from the transformer, the more the transformer would draw from its input, the more it would draw from the generator, the harder it would be to turn the turbine, water wheel, etc, and the more fuel you need to burn to make it turn, or more water you need to release to turn that turbine. Your power plant is running like a EV or hybrid's regen braking. If you try to charge your battery you will slow down your car. If your battery suddenly get disconnected or your regen braking stopped working when you brake, then you lose your brake, and you have to slow the car down with brake pads.
This is why people who says "free energy" have to understand physics and where all the free stuff come from. Either they get it for free use it or lose it like solar and wind, or you use up something by cooling off a big underground water source, or drain more reservoir water, or burn more fuel, or let the nuke reactor core run more atom split, etc.