What is the worst thing you've ever done to a car to make it workable?
i.e. I don't have the money to fix it right, so out comes the duct tape.
Worst for me wasn't my car, but I helped my buddy do it... He had a '96 Cavalier. The front section on the frames of the J-bodies are extremely weak. If you hit anything in the front, the whole front of the car will come back and the door will buckle the quarter panel the next time you open it (seen this a few times!). This was not what happened to him, however. This was even worse - 2 people got in a fight beside his car while the door was open, and one of them got pushed in to the inside of the door, pushing it forward and bending the mount / frame.
So, his quarter panel was all buckled at the back edge, and it scraped the door and made awful noises whenever the door was opened and closed. He didn't care about the car anymore, but wanted the awful noises to stop. We took an old pair of hedge trimmers to the sheet metal. They worked surprisingly well, and we were able to cut off the offending folded over edge of the quarter panel. It didn't look very good when we were done, but then again it didn't look good to begin with, all folded in.
He actually drove it like that for about 6 months before getting rear ended by an ambulance(!!!) and getting pushed into a Jeep. Finally the insurance company gave up and said the cumulative damage was a total. Poor, poor Crapalier.