Everyone (I assume) has a story of some game that they lent to a friend and never got back, or sold to EB only to regret it a few days later, and it's always some game that they know now was totally NOT a game you should ever let your hands off of, but gave it away anyway...
I have two games like that. When I was around 8, I lent my cousin (who lived in Alabama) Final Fantasy for the NES. I didn't see the guy for years afterwards, and the first time I saw him I asked about it... and it had gotten stolen from his house, along with all of his other games and systems. That game is one of those games that just should never leave any good gamer's possesion once they get a hold of it...
The other one, the one that I constantly cite as my worst decision ever in the history of my gaming (except calling Hoth the hardest level ever in LSW2, I'll never be able to live that down apparently) was the decision to sell Chrono Trigger for the SNES to what was then FuncoLand. At the time, it seemed like a good idea. FuncoLand actually traded games based on their value and demand, so I got a cool $100 or so for it, and promptly bought... fuck, I forget, but whatever it was it clearly wasn't as awesome as Chrono Trigger. To this day I wish I had that cartridge so I could proudly hook up my SNES and play it. It was a terrible, terrible idea.
So, now that I've bared my soul for all of GFF to see, what decisions related to gaming have YOU made that can only be classified as colossal blunders?
Jam it back in, in the dark.