Just last weekend I changed a light fitting in a neighbor's house. The fitting which came down had three 60W lamps, and everything had been connected together using what looked like about #24 telephone wire. There was no ground on the metal casing either, and the plastic on the terminal block had melted to the extent that it had sealed over the access to the screw terminals.
This is actually a house I wired start-to-finish about 4 years ago for the GC who lived there then. The present owners have also found a lot of other things he's managed to mess up along the way.....