What do you regret passing up?

[packs]

I didn't pass on them, but I had the deal blown for me by some nosey guy. This was back in the early 90s at a Gloria Rothstein show. I was maybe 13 at the time and was looking through a book of 1952 topps cards. The dealer had to do something so he had his buddy handle things while he was gone. I'm flipping through the book asking prices and the guy says, "Everything in that binder is $20." Most of the cards were beat up commons but in the back was a page with the Eddie Mathews, Jackie Robinson, and Bill Dickey cards. These were in amazing shape. I pulled them out and asked the guy again how much. He said $20 bucks each. Right before I can hand him the money and get out of there, some jerk next to me says "You're selling that Mathews for $20?" Then the guy's buddy pulls out the price guide and quickly puts the cards away. I could have killed that guy. Those cards alone would have paid for my college education.