My body must have a high resistance because I used to kill the lawnmower by just grabbing the sparkplug. Goof around with quartz BBQ igniters all the time, I zap myself a few times to show people they don't hurt then
when I nail them with it.
I also have a spark igniter for a furnace mounted on a board that I love showing people the spark jumping 2" to my finger.
Haven't yet built up the nerve to try and stall out a car by grabbing the ignition lead but I've seen it done.