Be careful out there!

Horror stories are good reminders of how quickly something can go awry. I did some silly things as a teenager with bumper jacks, but I did use them just long enough to get stands under the car. A friend didn't bother with that for a quick repair and his car fell on him. He had only minor cuts and bruises and was able to extract himself, but we knew it could've been far worse.
Another friend got crushed under an industrial forklift. The seals in the jack let go and it wasn't on stands. He was very lucky there was enough clearance that he wasn't instantly killed, but took quite awhile to get the machine off him. He's had serious medical issues ever since, and he hasn't really been the same person. Having a beast of a floor jack doesn't mean a 50-cent seal can't ruin or end your life.
I've been careful since the bumper-jack days, especially since I've lived alone for the past 20+ years. I rarely have company while wrenching, and the dog doesn't know how to dial 9-1-1. If something were to happen to me, it's doubtful anybody would notice until they were annoyed by loud music still going at 2AM or I didn't show up for work.
The worst thing that's happened to me was while a friend and I were pulling a car onto a trailer with a come-along. The column was out, so I was "steering" the car by manipulating the LHF wheel. He was going like a madman with that come-along when the wheel snapped to one side with my hand behind it. He wan't aware and kept winching, the car being pulled forward and down onto my arm while sucking me further into the wheelwell. "OK, stop... stop! STOP!! MY ARM'S CAUGHT!!" When he did stop I was in a curious position, pulled almost to my right shoulder into the wheelwell. Simply removing tension on the chain hoist made it worse, and my hand was no longer on the sidewall to pull on the tire. We had to jack the car up with it half on the trailer and partially remove the wheel to release my arm. That took awhile--he had to fetch the jack, chock the wheels, lift the car and undo the nuts. Thankfully, it hurt quite badly the entire time so the lesson was well taught. Even more thankfully, it was a come-along and not the 18,000lb winch he now has. That would've at least broken my arm if not removed it.

We're all still here to discuss safety (and I'm still able to operate a 4-speed). Let's keep it that way.