As in the title said, what are the watch u regret selling the most? it could be something u bought back again or something thats either harder to get now or the price is too dumb for you to buy it again.
for me its the Seiko Presage Fuyugeshiki Limited edition. sold it at a decent profit and use it to fund my other hobbies only to regret it a year later and can’t get one now because the price is too ridiculously expensive for what it is.