As you work with more fans, it's undoubtable that you will come across some fans that have been absolutely butchered by kind-hearted souls of its past history. What does this mean? Basically that you're going to have to do undo a lot of other peoples work. Never kid yourself into believing that any fan you own is 100% "original." Considering these are work-horse appliances that have been used for over 100 years, it's much more likely that your fan has been painted, re-wired, and had a replacement part or a few added to it over the years.
So here's an example of what not to do when you're re-wiring a head-wire on your fan, I'll let the pictures speak for themselves!