I passed on a "demo" (Whatever that means, it looked NIB) Sig 320 Compact that someone I knew had three of them for an insane price just before the news broke about the drop fire stuff. The one he kept is at Sig now, getting the upgrade/recall done on it.
I've owned a lot of guns since I turned 21 that I really wish I would have passed on. Some cheap, most expensive, all stinkers. To this day, the most expensive gun I ever bought was a Colt Combat Commander. I sure wish I had passed on it, but it was so pretty sitting in the display at the store near my old house. Absolute garbage.