I've had a few....
A few years ago I was trying to sell this, a 1998 Gary Fisher Joshua X0, BIGGEST buyers remorse ever. I bought this bike my senior year of college brand new, paid $1070.00. Thinking I'd love the full suspension and I'd be riding it all the time (like I had been until this point) then I graduated, got a job and got married and this bike sat and sat. I never liked the full suspension and when our 10 year anniversary was upon me and I was out of work, I sold this bike to buy my wife an anniversary gift and had enough leftover to get me a used (but newer) Gary Fisher (hardtail).
This little guy was found in a ditch and given to me. I cleaned it up real nice and rode it around some, really liked the springer and the feel of the whole bike (minus the banana seat) but eventually realized that I wasn't the person to appreciate it. Seeing other repops go for decent money I tried and tried to sell it and the only bites I got were from states away where I'd have to ship it. Finally my sister called interested in the bike for her daughter and asked the price, I said I'd give her the family price of $50, then let her buy me a BMX saddle, seat post, and 2 tires off of Amazon that almost added up to that amount. I was happy to see it go.
Most recently I'd been trying to sell this bike, a 1989 Schwinn Prelude with an Aerospoke rear wheel. Great bike, it was given to me by a neighbor, everyone either wanted just the Aerospoke or the bike without the Aerospoke, I didn't want to end up with piece of a bike that would be even harder to sell. I had promises to buy that fell through, calls, texts, e-mails and never a commitment.
Finally I just traded for these 2 beauties, who got the better deal? I don't know, and even though the Prelude was an awesome bike, I was glad to see it gone.
In some form or another, I loved all these bikes, but sometimes it's time to go!