My Dad once sold a house with a hand-shake. We lived in Alaska and when we moved back to Oregon in 1940, he sold our house to a stranger. A year later it burned down (accident with the kerosene lamp ... no electricity) so Dad told them he was sorry about their misfortune and cancelled their debt. I don't recall the original agreement, but they did owe us some money. Mother wasn't happy. I was 8 at that time and clueless.

Somewhere along the way buying and selling got complicated (home mortgages) and look where we are now:

https://www.nytimes.com/2010/01/10/magazine/10FOB-wwln-t.html?em

Dad avoided legal contracts and died at age 90, debt-free. We sold his Honda to pay for the funeral.

He wouldn't understand why I now have a four-drawer file cabinet in my bedroom filled with documents requiring notarized signatures.