I hope I wasn't somehow advising people to try this.
There is a non-zero probability of death.
Safety first!
DJ is 100% right about the current killing you, but you must be grounded. The current must go through the body.
If you are grounded, even by some measurable amount, and you hit the hot wire first, the juice can go through the heart, nerves, etc, and that 15-20 amp breaker won't trip unless it is "protected" (GFCI etc.)
Now, if the instructions said, "Stand barefoot on a wet concrete floor. . . " or "Grab the faucet with your left hand . . . then . . . " BZZZT! Severe and possibly deadly shock.
One of my jobs, in ages past, was testing wet-use electrical equipment for voltage leaks.
When the insulation gets old it loses dielectric strength & it leaks electrons. It leaks a lot more when things get wet and dirty, because the dissolved minerals carry current well.
I have taken shocks in the 1 to 10 milliamp range when I did something stupid**, and while 1/1000 amp tickled, 10/1000 is a shock.
Damn! DJ now you have me worried about this electric car BS. Those things can deliver a jolt!
Our neighbor just went through a FD training course on putting out electric car fires. How to find the disconnects on which car, what to do otherwise. These things burn up fast and hot in a real crash. It takes 3000 gals of water to cool a flaming Tesla. My desires to own a high tech car have fallen to zero.
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** I plugged a wet sewer snake into the test socket without checking the main switch. Someone had left the switch on, and I didn't see the meter lights glowing because of bright daylight on the machine. After that we moved back into the shop, in the shade.
I have also taken shocks from spark plugs and CRTs (TV tubes, in the 60's) and I don't advise it.