Lessee...
Chrono Cross- I just didn't like the magic system in this game, and I quit on the second disc about a year and a half ago.
Mark of Kri- Lots of fun, but the stealth aspect of the game gets traded off for a nonstop killfest in the last level, and I gave up. Chances are I was only two or three rooms from the end.
Super Mario Bros.- I never finished this one either, and it still bugs me a little.
More than starting games and not finishing them, I'm bad about buying too many games and never getting around to playing them. I go to a lot of pawnshops and when I see a game there I've heard good things about for $10 or so, I have to pick it up. A few that have never even so much as made it to the the console are:
Resident Evil Zero
Skies of Arcadia Legends
Legend of Dragoon
FF IX
Fear Effect
Dragon Warrior 7
Vagrant Story
I know, I admit I have a problem. It's the first step on the road to healing.