A friend and I played through Left 4 Dead 2 on Expert our first time through. It was... an experience. Hoo boy. It didn't go dreadfully bad most of the time, but there were some parts we were stuck on for hours and hours. We managed in the end, but it was quite a struggle at times.
Thinking of Halo, this one is kinda mean. x) I was babysitting one of my mom's friend's kids when he was around six I believe and we both wanted to play Halo. Well, I wanted to play on Legendary because I was having too easy of a time and he didn't have a choice but to go along with me. We actually did pretty well up until the infamous Library level when we were stopped dead in our tracks. Things turned sour. He started throwing tantrums whenever he died and I kept getting murderized by just myself, but I wanted to finish it regardless. He stopped playing and I bashed my head against it for awhile before giving up. I hope whoever designed that level steps on some Legos with bare feet, though I probably deserve the same fate as well.
Any difficulty other than what would be considered Normal in the Civilization games. I've played the series for hundreds and hundreds of hours. Occasionally I'll feel a bit spicy and decide to bump up the difficulty a couple notches and I end up getting humbled quickly. I have similar trouble with the Total War games. I enjoy both of those series, but ultimately I'm not that great at them.
Similar to above, fighting games in general. Again, I can handle normal, but any time I've tried going higher has resulted in disaster. I'm too impatient and button mash too much to be actually good at the genre.
I've modded the Elder Scrolls and Fallout games more times than is probably healthy. The last few times I've used modpacks from Wabbajack. They almost always recommend or even start you out on the higher difficulties, in addition to being rebalanced to be harder. I can't handle it and I don't know how people can. You die in a matter of seconds! Miliseconds if you're unlucky enough to aggro a group. I suppose it gets more reasonable once you're better equipped and have some levels under your belt, but I don't even know how to get that far. x)
Like above, the S.T.A.L.K.E.R. mod community is just filled with masochists. Misery is a very apt name for that (in)famous mod and all the rest are just wolves in sheep's clothing. S.T.A.L.K.E.R. is a series that is very important to my boyfriend and even though he's great at the games, he agrees the difficulty from the mods is just bullshit.
To continue the trend, RTS games in general. I have difficulty even on normal with them, let alone anything above that. My ability to multitask and focus on so many units and skirmishes and base building and... and... it's just all bad. I can do okay at a handful of them, but most are far beyond me. I remember playing a VS bots game in Starcraft with a friend and my lack of skill pissed him off so much that he refused to ever play with me again. x)
The Fire Emblem games on Lunatic and even Hard at times. When a single point in Speed will determine if your character is useful or useless because they can't double, it's too much for me, especially with the random stat growth. I will also turn off permadeath if possible, because I'm weak.
Once upon a time I was actually pretty good at F-Zero GX. Not amazing, but none of my friends could stand up to me. I was good at everything below Master, but once I hit Master I started hitting a brick wall. I managed the Ruby Cup on Master, but couldn't get past the Sapphire Cup on Master. I beat all the Story stages on Normal and most on hard, but Very Hard was too much for me. I think I simply hit my skill ceiling. I'm proud of how far I got though, it's not an easy game.
Ninja Gaiden: Black on Master Ninja was just not meant to be. I got a bit into the game, but it was just proving too much for me.
Shinobi and Nightshade. I just don't think I have fast enough reflexes.
Wow, that's a lot of games I'm kinda bad at.
