I used to do CAD/CAM programming for a steel company, bridges were my main thing. We had a huge project for a tram at DFW. Everything on my end was correct, but the shop not so much. They assembled the girders together at the shop before sending them out, so there should be no problems. But when the workers at the site put the girders together shit was off by a couple inches. We were getting ready to send our bridge inspector out to determine a fix for it, so he stopped by my office to ask me what measurements I would need to make flanges/webs to correct the mistake. Once he explained to me what the problem was, the first words out of my mouth were "Holy shit, who fucked that up?"
The look on his face told me exactly who fucked it up.
If you're ever at the DFW airport, walk.