Here's one:
I bought a set of five 6-hole 16" wheels from a junkyard to put on our old Suburban. The bolt pattern was correct but the center hole was too small, so I got a neighbor to cut them out very nicely with his plasma cutter. It seemed like a good idea at the time.
Well, it turns out there is this thing called "backspace"
The wheels fit perfectly, except they go in too far and hit the tire rod end and won't rotate. But of course I had him do
all five at once instead of just one to see how it fit. So I couldn't take back any of them.
Since then I bought a GMT400 pickup which the wheels originally fit, but I'm afraid the wheels aren't safe to use with only the lug nuts for support.