I've been asked to repair wiring many times. Some of the stuff I see is downright terrible. One of the problems is that older homes are many times under-wired since the demand for power was less than it is now. Someone will try to add on to existing wiring and wow...nightmare time! Nothing grounded, solder instead of wire nuts, everything you can imagine.
When my brother bought his house...and it's a nice house, the wiring was so bad I was getting shocked off of the garage door and heating ducts. I at least made it safe until he got an electrician to redo the panel. I managed to fix outlets and get take some of the old PH 40w fixtures and replace them with new ones (I kept the old ones). One of the old PH fixtures had a bad ballast that shorted to ground, but since it wasn't grounded, I was getting shocked touching the fixture...ouch! Also, the ballast blew out the filaments of a nice vintage westinghouse bulb. Anyway, electrical stuff is nothing to joke around with.