I rode with a cousin in her car the other day for a short trip. When I opened her car’s trunk, I found it full of things that she doesn’t use regularly. Like the 2 folding chairs and a beach umbrella that are for picnic purposes. There’s also the gallon of water for the radiator which I think a liter would be enough. And she was surprised when I told her that extra payload consumes gas. With that, she promised to clean the car trunk of excess payload. Think of a heavier payload when going on a long trip, that’s a lot of extra gas.