Except the #1 thing you are washing off is the natural oils from human skin and sweat.
And #2 and #3 are the oils in food (chocolate, grease, wine, and other food products) and then the oils from grass / outdoors.
Literally the only thing that water helps with is soil / dirt. Outside of that, the washing machine should be designed to use the minimum amount of water needed to activate the soap, the actual cleaner.
