Final Fantasy 8
First try I got to the start of Disc 4 when you're on Lunatic Pandora and have a boss fight vs. Adel. I was severely under-leveled (all characters around level 35 iirc) because that game is totally borked. You can't leave Lunatic Pandora and all the enemies only give 1 exp per battle, so I had no way to level up. I had to restart...
So second try I get my characters to level 89 on Disc 1 and max out my GFs. I did that over end of term break from school by fighting Vysages for hours in a certain part of the world map prior to the forest on the way to Galbadia Garden where they were the only enemy encountered. They're super easy to kill and give levels extremely fast--no idea if that's the most effective strategy at that stage of the game, but it's what I stumbled upon and chose to exploit. It was the most boring grinding ever. Anyway, I continue on to the end of the disc and boom... corrupted save data when trying to start Disc 2. I foolishly had been using only one slot. The memory card was fine, just the FF8 save wasn't loading. I assumed at the time the game couldn't handle the fact I was so over leveled, though I don't know if it's just a coincidence or not.
Never beat that game. Though I did play it again and get past Adel with a normally leveled party. Then I lost interest in finishing it.