I've lost and found lots of great things ... including huge financial deals in my life. On balance I'm definitely ahead of the game. Here are a few of the interesting ones...
Found a Spyderco lockblade when I was living in Colorado. Public suburban street. It was laying on the edge of the road in the drainage area. Badly abused, broken tip.
Sent it to Spyderco and they are an awesome company with a great warranty. Received a brand new one in the mail a month later.
I was impressed. Still have that knife.
I've also found 2 rings. On a canoe trip with coworkers and their friends, there was some horseplay in the river. One guy called time out as he lost his wedding band. Nobody could find it in the water, and we have been drifting down stream. Against all odds, I saw it glint in the sunlight. Was a really cool feeling. I gave it back to the fella, and he was not nearly as appreciative as I would have expected... still annoyed by that.
In a parking lot, I stepped out and found a beautiful diamond ring. It had been run over and flattened, but the diamond was stunning. Nearby it I found a single beautiful diamond earring. I couldn't imagine what had caused some upset fiance or wife to toss her ring and earrings in the parking lot! As I took it to the jeweler to get it appraised, I was already spending the money in my head... a few mortgage payments, maybe a new handgun. Cubic zirconium.
I took it to 3 jewelers to confirm. They were all expecting it to be real. Sadly, it was junk.
I've "lost" out on a few amazing deals in my life. Gun related, I passed up a rare Hipower but a buddy snapped it up. It was worth 5 times the asking price. I also passed up on a Python that was worth well more than the asking price. In both cases, I had the cash but was too foolish...
In the military lost equipment is common. One I recall was a SF E7 who set his 1911 on the fender of the MRAP, put on his kit, and climbed aboard. A few miles down the road, he realized his holster was empty. Gun had long been lost and likely snapped up immediately by a local.
I nearly lost something very valuable once in the military, in Iraq. I luckily did not. It would have ended my career. Thank GOD I didn't lose it. Losing stuff can truly happen to anyone. We are all accident prone.
Non-gun, but significant. I purchased a new home directly from the builder. No realtors involved. We sat down, and he completed the contract from a form, filling in the blanks. He wrote in the purchase price $xxx,xxx, signed it, and left the table while I reviewed it. I noticed the price was a full ONE HUNDRED THOUSAND $ less than we had agreed. I could have simply signed it, and taken the copy, and profited $100,000. But being the honest person I am, I notified him and we corrected it. I have to say though, that when faced with that situation, even the most honest person can be tempted ....