I was wiring a new kitchen for a customer and they commented on how they kept getting a shock from light switch and had been for the last 10 years since they bought house. The lighting is wired in twin (no earth ) so had to explain that all metallic switches and lights would have to be changed to type that needs no earth. Customer thought I was at it what chance do you have also were a bit miffed as the sockets above worktop brushed steel but light switches changed to plastic also pointed out no provision of earth warning sticker for lighting circuits that I fitted to recently replaced all rcbo consumer unit done by a family friend (no paperwork for consumer unit ) also pointed out same noted on cert to cover my backside. I mistakenly thought I had seen most stupid things but mistaken