I was playing Pokemon Firered, trying to capture Mewtwo with Ultra Balls. (Everyone know its hard)
After resseting 10 times, using about 70 ultra balls per try (I'm not lucky), I finally captured it.
I dropped the Gameboy.

It also happenned for Regice, Groudon, latias, and many others.
And I ALMOST dropped it for Shiny Nidorino!
Now, I'm very carefull when hunting for shinies.

Zelda: Ocarina of Time: On my first playthrough, I read about the extra bottle glitch. And I thought "Well, these bombchus seem pretty useless!" And replaced 'em with a bottle. Then I got to the Spirit Temple and my blood went cold as I saw there were parts of it clearly intended for Bombchu use. But I managed to clear it with normal bombs and breathed a sigh of relief. But then I got to Ganon's Tower, where you DO, ABSOLUTELY, need a Bombchu. For one switch in the entire game. I got that close and had to start all over again. Of course, it's nothing now, I have learned the ins and outs of the game like the back of my hand and have beaten it several times, plus Master Quest. But for the first playthrough (also my first Zelda game), that is a bitter, crushing lesson.

Kid Icarus: Uprising:
Highlight to view spoiler.
When I finished the chapter where Pit and Pittoo fight the Chaos Kin to de-brainwash Palutena and Pit's wings burn up as he saves Pittoo from certain death... the cutscene showing Pit's brutally scorched wings, smoldering, [i]bones exposed...[/] Then the cheery Chapter Clear music starts and I am told that I unlocked the power, Burn Attack.

Animal Crossing: I played it. And I can never get that time back to spend doing something good.

Omg! That must be frustrating!
On my first playthrough of this game, I was stuck upside down in the Forest Temple with those creepy hands. This Temple is so scary!
Also, what's the difference between Ocarina of Time and Master Quest?

Master Quest is the same as the normal game except the dungeons have completely new puzzles, moved treasure chests and items, a lot more monsters, sometimes more dangerous monsters, and the Gold Skulltulas inside the dungeons are mostly in different locations. It's different enough that you'll find yourself working through the rooms of a dungeon in a completely different order than in the original game. The Water Temple is actually easier to figure out in Master Quest, though. Nothing outside the dungeons is changed. Since all Heart Pieces in OoT are outside the dungeons, those are all in the same places.

In the 3DS version, all maps in the game are also mirrored, so east is west and west is east. And Link is right-handed. And I think he also takes more damage? I don't know.

Yep. It also happenned for Twilight Princess on Wii.
On Gamecube, Link is Left handed.
But most of the people are right handed.
So if you choose to be right handed, everything will be reversed.
My friend is left handed and the map is the original side.

The game doesn't offer an option. The Wii version is flipped and Link's right handed, no matter what you think about it!

It's a bit silly though. Wii Twilight Princess' motion controls amount to nothing more than: wiggle the remote to attack. I'm right-handed but it wouldn't have made a difference to pin the same controls to a left-handed Link (in fact, there's a hack that flips the maps to match the GameCube version, makes Link left-handed, and I've played it without even noticing so much). Skyward Sword is a completely different story, yet, it offers no options for laterality either...

I just remembered a horrible thing BioShock (the 360 version) did/is doing to me. I have gotten all 50 of the original achievements. But there's one more on the list, a secret one that doesn't tell you what it is. This is "Brass Balls," unlocked by clearing the game on Very Hard mode without dying (in other words, reloading a save every time you die instead of respawning at a Vita-Chamber).

I could do that. It would be frustrating but I could do it. Except. That's an extra achievement you're not supposed to have on your to-achieve list unless you get a DLC package that includes new plasmids and other things... including Very Hard mode itself. I literally cannot get that achievement because I don't have the mode I have to play to get it. And I don't have an internet connection for my 360 either. At least, not at home.

Of course, it's just as frustrating when primarily single-player games have achievements exclusive to the online parts (I am looking at you, Dead Rising 2. Dead Rising 2, why can't you be more like your big brother Dead Rising 1? That game only had offline achievements and wasn't half as glitchy as you are), because I can't get those either.

Oh well

i was playing halo (or halo 2 i cant remember which one it was) and i fired a rocket at someone, i died before the rocket exploded, respawned to my rocket hitting me in the face >.> gotta love instant respawns

in a halo 1 match i sniped myself....i shot a tank (trying to snipe the driver) it ricocheted around a couple times before returning to my face....it kinda was an epic shot but rather terrible consequence

Oh that's easy. Two.

First time playing Halo. Due to me going a bit too hogwire on a chopper, my score was -2.

Second, losing to a spammer M. Bison on SSFV3DE because I dropped my phone. The salt ensues.

Shall I mention the ending of the second-to-last mission of CoD 6?

Why does it seem that everyone has a problem with the ending of MW2?
I hated Black Ops for Reznov's character storyline, but no, MW2's ending sucks.

I think my worst was once in Pokemon HG. I had played a really long part of the game, something like 3 or 4 Gym Leaders and everything in between. And when I stopped, I did the most stupid thing I could: I switched off w/o saving. I still don't get how I did that.
A really bad moment for my gaming was also when I realized that the Dream Radar was not free. I don't have a credit card, and e-shop cards aren't sold in Greece. So my chances of getting the game are pretty low.

[angryrant]

In the 3DS version of Zero Escape, I was unfortunate enough to trigger a bug in the code. By saving the game in the PEC room, you permanently corrupt your save data, forcing you to restart your game. I had invested over 20 hours. The game is story based, so I was avoiding looking online for info due to spoilers, and I therefore hadn't heard about the bug at the time. They REALLY need to made a downloadable patch to fix the problem, the Mario Kart 7 one was very trivial by comparison.

[/angryrant]