You know, after all of the many monitors and television sets I've repaired over the years, I've never managed to get a "full zap" from a running set. Couple things I have managed to do, however:
Zenith console TV - tube type, 50's era. Had the chassis (big metal thing with picture tube mounted to the top) on the bench. Removed the picture tube to turn the heavy metal chassis over for a lengthy capacitor replacement. Reinstall the picture tube, test, find something else awry, remove picture tube, repeat. Test again, reinstall the tube, connect it up... tube lights up - awful dim, but working. Hissing noise. Notice that I never actually reconnected the anode lead, and it was hanging from a holder, two inches from the tube, arcing to the anode connection...
Computer terminal - 80's era 12" monochrome text terminal. Doing the usual "why no HV" dance - replace a part, reconnect, repeat... Get overconfident, go to disconnect the anode again, only to find out that apparently that cap I just replaced actually did bring the HV back - ZAP! That hurt, but it wasn't too bad, since it was such a small set.
Electrohome G07 arcade monitor - accidentally plug the video cable in off a pin. Cabinet has poor access, so I discharge the tube to avoid zapping myself as I fumble around to move the connector. Afterwards, I powered up the machine to a Fzzzzzzzth! Silly me left the screwdriver under the anode cap, jumpered to the frame with a clip lead. Blew the small fuse on the chassis, but no other damage.
And, of course, I've gotten bitten by the filter cap on a G07 chassis once, and installed a cap backwards on an exceptionally charred G07 (board markings gone) and was greeted with a nice hissing poof on powerup...
Actually, the most painful electric shock I can think of was that time I was tinkering with the phone line when was like 12 years old. I was using uninsulated metal pliers to tightly twist two hard to reach wires together inside the wall when the phone rang. That phone ring current is like 20Hz and it REALLY hurts - it twitches your muscles something awful. 120v wall current doesn't even hurt that much.
-Ian