Do you have a gun you regretted selling later?
I look at my guns as tools so I don't really get attached to them. I like some of my guns more than others because they are more accurate, reliable, functional or pretty but not really attached to any of them. If I'm offered a fair price for any of my guns and I'm not using it at the time or in foreseeable future then I have no issues about selling it.
When my wife was pregnant with our son I was around the house all the time and in the evenings I would hangout in the garage working on little projects. One night I was cleaning out my parts bin when I realized I had a Norinco 1911 frame, almost new Colt barrel and an old Springfield slide...most of the parts needed to build a 1911A1 pistol. Next night I started getting and fitting all the parts together. For next 5 months I would sit in the garage to order parts and fit them to build a 1911 that I wanted. 10 days before my son was born I finished fitting all the parts and refinished the pistol with bake on moly finish.

Certainly not the quality of master builders of the time but very respectable pistol that was totally reliable and very accurate...and in my eyes a good looking pistol. I carried that pistol for almost a year and shot thousands of round through it at local IDPA, IPSC, bowling pin and 3 gun, bullseye, etc. matches.
One day at the range a fellow approached me and asked about the pistol. He shot couple mags with it and asked me if I would be willing to sell it. I told him for the right price I would sell it. After few minutes of negotiation we agreed on a price and then he left for few minutes to go to the bank and came back with the cash. He gave me cash and I gave him the pistol...no regrets.
It was couple weeks later that I started having regrets. I've tried to track down the guy but nobody knew who he was.
That was 13 years ago and I still have regrets about selling that pistol.