You work at a car rental place, at an international airport. You go to work every day, do your thing, but there's been one car you've had your eye on.
It gives a twinkle in your eye. It's shiny, when you drive it round, it purrs. It seems to be everything you ever wanted.
You'd never buy it though. It's got roughly 180,000k's on it. Since it was a design on a piece of paper to where it is now, it's been through hell and back. You've seen people rent it, throttle it, seen it serviced countless times for ongoing issues. It breaks down when you need it most, and you don't know what will go wrong with it next.
Don't buy a rental car. Don't marry a woman with a high partner count. You know everyone has had a good throttle with her, and you don't know what will go wrong next.