I can not remember, but it probably caused a void which needed to be filled, resulting in the incentive to repeat what I seem to be good at.
I have tried selling some stamps on eBay but later realize I better keep those stamps. Besides, no good offer for those I have tried to sell.
At first it felt good to have some extra money in my pocket. But then I started missing those stamps, and I wanted to get them back somehow. I advise you not to sell your stamps if you get attached easily to things.