When replacing a ceiling light fixture with a ceiling fan, it is critical that the electrical box be able to bear the weight of a ceiling fan...and be level! Fortunately, the existing box was a fan-rated box, but it was not level. Light fixtures are "forgiving" and can often be installed on a box like this, but not ceiling fans. I wondered at this point what the problem was....
Much better!
....So into the attic I went, and found....
....What the....?
Seems the licensed electrician who installed this thing thought it was OK to take a shortcut in securing the box to the bracket, since he was only hanging a light fixture from his work. But then I come along, have to hang a ceiling fan from it, and get to fix his mess. So that's what I did....