There was one particular time playing C&C Renegade (one of the best and most underrated FPS's I've played) when I drove my vehicle to the base and fired on one building for at least 10 minutes before realizing it was already destroyed. Oops.

Awhile ago I was playing through Ravenholme in HL2 and I got to that part when Father Grigori tosses you the shotgun and you have to fight a bunch of fast zombies on a rooftop. I was backpedaling away from one and fell off the roof, and I landed right on top of a streetlamp. I like to imagine that it was like in a comedy movie and Gordon landed right with the lamp between his legs and against his junk and he'd make a funny face and be all like "OOOOHH"

I have just had another felt this just needed to be shared. I was playing DMC4 trying to finally finish DMD mode (mission 19 i'm close)I had just slaughtered two Blitz' but i landed on another red space so the game set a few scarecrows lose on me, I tried naturally to show of some of my awesome moves on them and got about 10 blades up my ass and found myself dead. I seriously don't believe how close i was to the end and got cocky.

My biggest fuck up was playing Final Fantasy XII and walking into a cavern with a creature called a Nightmare and thinking "Oh I can kill that" and having it Teleport behind my characters, block off my escape, and slaughter me. Here's the kicker, I hadn't saved in about four hours because the cage was connected to low level fights. I was level 16. The Nightmares were level 46. Needless to say, I stayed away until I'd hit level 52.

My most frequent blunders (each one more embarrasing than the last) occur in CSS. usually involving me throwing a grenade that bounces off the wall and taking out me, and my entire team. On the good side, i'm often considered a hero by the other side. :(
Oh, and recently i managed to persuade/bribe/threaten a few friends to play a game of Baldur's Gate 2 with me. Arrogant asswipe as i am, i bragged how good i was, and that this wasn't going to be a challenge without some difficulty enchancing mod. In the heat of a early battle, i mis-took magic missile for fireball, and fired right into the group.... Last time i ever take my skills for granted >.<

War Monger of Yabucua:
I remember when I was playing Crackdown, I was trying to take out the Kingpin of the Asian gang, which is on the top of this very long building, I could'nt jump over to where he was so I fired grenades and rockets at him, when suddenly, one of his guards throws a grenade at be, sending me flying of the building and to my death 40 stories bellow(that asshole).

you weren't the only one that happened too.

When I first played FF7, I messed up royally with the scorpion robot you fight with Barret in the reactor. I read it as "fire when it's tail is up" and missed the "and it'll counter attack" as it was just a broken up window. Yeah, got my ass handed to me.

Part two of this was that I forgot how to get out of the reactor, and it blew up with me inside it. FAIL.

Also when I faced Sephiroth in KH2, and I thought I beat him but the screen didn't slow down as it does when you win a boss battle, and I put down my controller. He killed me right afterwards, the cheat!

I lost a team of 25 highly trained men, armed with power armor and heavy plasma rifles against 1 Chryissilid.

Because I made one mistake and that one Chryissilid turned into 2. Then 5. Then 10. Then 20...

Losing to a pair of grade a spackers on Pro Evo 6 online.

They played 5-4-1 formation, and scored a late header.

Pad through screen.

fsanch:
There was one particular time playing C&C Renegade (one of the best and most underrated FPS's I've played) when I drove my vehicle to the base and fired on one building for at least 10 minutes before realizing it was already destroyed. Oops.

Another Renegader! :D

I never did that, but I once lost 3 tanks to the other team in the same game :<

Wazzelbe:
Playing TF2, I thought Demoman sticky bombs were proximity mines.

Still playing TF2, I thought spy sappers were meant to be deployed as claymores on the wall.

In portal, I carried a chair from one part of the level to the other and used it as a stool, when I apparently should have used a sentry's rocket to blow open a tube and use the resulting cube as such. Whoops.

I did that too!!!

Yassen:
it would have to be the first time i played twilight princess. i spent 2 hours trying to figure out how to fish using the fishing rod in the first area. i almost threw the wii remote through the screen. lol

I did that exact same thing.

I was playing as Pit in Brawl. Me and my friend were battling on the Frigate Orpheon stage. I was using Pit's recovery just to piss him off. I said something like "haha you can't reach me" then the stage flips.

I killed a ton of people in a row on HL2 online. After feeling all proud and awesome, I get killed by a common house hold item.

Rocket jumping + me = massive amounts of FAIL.

When i played "Ty the Tasmanian Tiger" It took me almost the entire week I rented it it figure out that I had to hold the D-pad on the gamecube controller to switch boomerangs

Worst time was while playing battlefield 2, i threw a grenade at the enemy, but as i threw it i moved my mouse follow him, and the grenade was thrown as he went behind a wall, and of course it bounced right back at me.

I was killed by a bat in Ninja Gaiden(360), first level. Man that was funny, my brother was impressed by the slaughter of the infinite ninja room in the first level, and I ended up going down that hole and being brutally slaughtered by a winged rodent. We laughed our asses off.

I once spent an entire afternoon hunting down the 50+ remaining hidden packages in Vice City. I got to 90ish, then thought "Damn, that was a good afternoon." and switched off the PS2.

Que "D'oh!"

Jumping, missing the ledge, and falling multiple times into bottomless pits on the Star Wars Battlefront II Death Star stage.

God, I hate when that happens. It's especially bad when I'm playing AS A FREAKIN' FORCE USER.

On Eternal Darkness, I turned off the Gamecube without saving after the "there's a problem with your memory card" showed up. Damn Sanity Meter!

I still think it's an honest mistake, but embarrasing either way.

I was playing Roller Coaster Tycoon 2. I made my own coaster - it had 2 trains and could seat a ton of people (forgot which kind of coaster.) It looked awesome. Me as my cocky self, I am like "it's so awesome there's no way it can not work!" I refuse to test it out first. So people line up. roughly 30 peeps in train 1, 30 peeps in train 2. The train took some turns fine, and then it went into a steep dive underground. I had made a steep climb up (naturally)....and the stupid train couldn't go up it. Of course by that time train #2 had been merilly climbing to that same spot....so yeah, i screwed up pretty badly.
The worst part was I was playing in China, countryside, with my grandparents and my couzin watching me.
*train crashes*....my cousin and my grandparents look at me and they start laughing.

Uhh, sorry for the double post, but I might as well ad this one, since i thought of it now. I was playing Halo 3 on Heroic..crows nest i think. So I manage to pop all the Brutes in the room after Johnson tells you to go save the marines in the barracks. All the brutes, except the gravity hammer bitch. I take out my shotgun, put 3-4 rounds into him, go "Haha, I'll look SOOOOOOOOOOOOO pro like this!" I do the dumbest thing I have EVAR done - I melee him. Yes, I melee him. I go right up to him, his shields are clearly up (I missed the 1st shot) and I go "HAHA! I PWN YOU!" (Press B Button)
Brute: GRRAWRAWRAWRWARRGGFGARRBBQWHAKAMOLE
Poor Chiefy goes flying, and my brother, who stopped playing World of Warcraft long enough to watch, laughs at me.
2 minutes later, I clear all the Brutes again, and I put like, 1 clip of BR into him and he dies.
Hand meets forehead :D.

yanking my NES off of it's spot in the cabinet and somehow deleting my Dragon Warrior 4 save file during the end boss battle

Wazzelbe:
In portal, I carried a chair from one part of the level to the other and used it as a stool, when I apparently should have used a sentry's rocket to blow open a tube and use the resulting cube as such. Whoops.

Oh, I did that too... I went through all that trouble, and I found out that the trouble wasn't needed... Complete let-down...

stompy:

Wazzelbe:
In portal, I carried a chair from one part of the level to the other and used it as a stool, when I apparently should have used a sentry's rocket to blow open a tube and use the resulting cube as such. Whoops.

Oh, I did that too... I went through all that trouble, and I found out that the trouble wasn't needed... Complete let-down...

Ok, then that's mine, because I didn't even know there was another way until reading this. I did think it was kind of weird and that I was probably doing it wrong; the chair kept falling over. But...wow. That's just moronic. How did I never notice that?!

But this thread really reminds me of the funniest--and dumbest--thing I've ever seen in SSB: Melee. My little brother was playing as Dr. Mario, got himself a Bob-Omb, and, since we weren't exactly playing a serious match, announced he was going to waste it. So, he threw it at a wall.

This was an odd sort of wall, though, because the bomb bounced straight back and blasted him into oblivion.

One of us had to pause the game for a couple minutes because we were all laughing too hard to pay it any attention.

Does it have to be while playing the game?
I thought my hard drive was dead bc my oblivion files were gone but i was in the wrong gamertag.....
In game though was when i missed the game winning headshot in Halo 3 we lost 50-49.....

Every time I try to play a NASCAR racing game, I usually wreck against the wall or get hit by some A.I. driver who is passing me. The worst of all was the time in NASCAR 2006 (I think, since they are so similar) when I caused a multi-car pileup and wrecked most of the cars early in the race. If I'd been playing Burnout, I would have had a great score. I rent NASCAR games btw every so often when I momentarily forget how bad I am at them.

I couldnt pass the second fighter in Mortal Kombat II

Yassen:
it would have to be the first time i played twilight princess. i spent 2 hours trying to figure out how to fish using the fishing rod in the first area. i almost threw the wii remote through the screen. lol

I spent a good half an hour in the prison when you first become a wolf trying to get out. How was I supposed to know I could attack as a wolf?

In Final Fantasy III (SNES), I lost to the Ice Dragon.