You can't always trust people.
Marvin is on a road trip, driving on a freeway, when he sees a person hitchhiking on the side of the road.
Marvin wants to decide whether or not to pick up the hitchhiker.
Marvin decides not to be bothered and drives past the hitchhiker.
Marvin decides to help the hitchhiker, pulls over, and lets him in the car.
Marvin drives for another two hundred miles and then stops at a motel for the night.
Marvin gets robbed and has his car stolen by the hitchhiker.