Current, Voltage, and Power.

Current = analogous to how much room a fluid has to flow. There's a lot more room in a sewer, for example, than a straw. 

Voltage = analogous to how much pressure there is in a tank of water. If you poke a hole in a small plastic cup, water will spill out, but it probably won't burst out and hit you in the face. More than likely, it'll flow along the edge of the cup. But if you take a sledgehammer to a giant durable tank of water, the water will burst out. 

Now what happens if you take a little nail and hammer it into the side of the tank? The water will burst out, but in a narrow stream. If this was happening with electricity, we would call this low current with high voltage. 

The reason why we have unit called Power, where P = IV (Power = Current * Voltage), is because we want some sort of quantifiable way to measure both of these aspects combined. 

If we want to supply a lot of electricity to a city, we want a lot of power. If we have thin wires (low current) to transport that electricity, we'll need to have high voltage (i.e. from a power plant) to make up for it. And thin wires are cheaper than thick wires, so this is why power lines work the way that they do. 

Credit goes to Steve Alcorn's Theme Park Design course for finally making this click for me. 

Also, an lmao from the same section: