Having FF VII for two years before actually playing it through to the end.
Paying good money for any Sonic game since Sonic Adventure 2: Battle.
That the Halo and GTA series were ever made. It's a sad story, I liked the originals, but the franchise has become something evil and spews perfect 10/10 scores from its pores of dreadful gameplay and lack luster production. I would make the sacrafice.
Playing Dead Space for three days straight. Killed my PS3 disk reader- needed a new PS3.
That they never re-made or released a new version of Phantom Crash. One of my favourite games ever, but went completely below radar.
Any time I spent on an MMO. I can't think of a single decent memory. I just hope FF XIV will be somewhat different...though I have my doubts.
The short lifespan of the Dreamcast, it was so incredibly good I still keep it in my room.
Killing the Skingrad house salesman in Oblivion before I purchased the property. I shall never again have that mansion for my high level battlemage.
Buying Soul Calibur 4 based on the character creation- which proved to be nothing more than a pointless re-skin feature as far as I was concerned. Unlockable moves would have made the whole experience so much more awesome.
Buying Resident Evil 4 for the Wii a few weeks before my brother sold the bloody thing.
Spending hours playing Tomb Raider 2 and toying around with the stalking butler, going so far as to seal him in the giant freezer. I actually had nightmares about him when I was a little kid, following me around like a robot zombie...
I really need to stop now.