There are some games I love on one hand, but hate on another.

I love the original Road Rash on the Genesis, but I've never beaten it. It starts getting extremely difficult in the 4th level and starts pissing me off.

Resident Evil was great but I never actually beat it. Seemed to get really hard toward the end.

Same thing with RE: Code Veronica. I got stuck in the airship with the big ugly monster and saved with little life. Basically ruined the game.

Tempest 2000 is AWESOME but I've never beaten it without using a level skip cheat for several NASTY levels that are near impossible

Alien vs Predator is great fun but the Marine and Alien scenarios are extremely difficult. The Alien scenario really isn't that fun. The Marine is but damn, a lot of walking around mazes. Need a lot of patience for the game and even then, I'v never really come close to beating it without cheating.

final Fantasy X - Great game but I got owned toward the end over and over and gave up on beating it.

Grand Theft Auto 3 and Vice City - Fun games but they are so massive. Never beat either.

Zelda 1 NES, Link to the past, Ocarina and Majora's. All fun games, but never beat any of them. Just such massive games with so many puzzles. I get toward the end and it gets to the point where I'm more annoyed than having fun.

Rayman - great game but too darn difficult in later stages

Banjo Kazooie - great game but too massive

Cybermorph, actually is a good game but is hard and massive. I finally beat it after playing it off and on for over 10 years...

Then of course there are a ton of crappy games that are insanely hard and aren't fun at all. The games I listed are fun, but really hard to beat imo.