My worst mistake is also one of my best. Over 10 years ago now, I bought a Space Station at auction. The auctioneer screwed me on it (I wasn't the top bidder, but he said I was, I decided it was close enough to what I had said so why not), I vastly overpaid ($1200+), it was in crap shape and fell apart after about two weeks. I then started trying to fix it...

I've put over $1800 in parts into it, and it still looks like crud. If I was going to sell it in today's market, I'd be lucky to get $800 for it.

But... I met SO many people buying parts and trying to fix it that are still friends with me today, and who have helped me to find a million and one deals since then. Thanks to that overpriced SS, I rarely paid over 75% of "fair market value" at any given point on a pin since then.