I hate it when I do stupid stuff

Guy that lived across the street from me had been out all day on a saturday working on his sons old pickup it was raining so hard they used some 2x4s and a blue tarp to make a shelter. They where out there till way after dark. Next morning I looked out the window and they where still at it. That afternoon I thought I would go over and see what they where doing. He told me they tuned it up yesterday and the darn thing will not start now.
I noticed sitting up on the fire wall was the rotor. Asked him if he put a new rotor in and he told me no the old one was fine. He was a little embarrassed when I picked it up and asked him if that was the one he was talking about.