I'll never forget the time when I was returning home in my Mom's car from my after school job only to find my sister's car in the driveway. Mom's car was quite old by then, and nearing the end of its useful life. The handle on the outside of the driver's door was broken, so you had to leave the front wing window unlocked so you could push it in and reach the inside handle to open the door. It's winter, mind you, and there is snow and ice on the street. I leave the car idling in the street to go up to the house to ask if I should park it there, or if my sister should move her car. She comes out as I'm getting close, and gets this wide eyed look. I turn around to see Mom's car rolling backwards down the street. Automatic transmission, but I hadn't gotten it all the way into park. (Old car, like I said.) There's a somewhat newer car parked half a block behind me. I have to run to the moving car, punch in the wing window, pull the inside handle, jump in and get it stopped! Fortunately, I made it on time.