What's your most painful blunder?

Chess can be the cruelest of games. I was just reading a book on backgammon by the two time world champion, Bill Robertie. In the book, Robertie spent some time commending an excellent play that had backfired in the game. He noted that in backgammon, unlike in chess, you are only rewarded for your good plays a percentage of the time. On the other hand, in chess we may not even be rewarded for forty good moves in a row. In chess more so than any other game, a poor move can instantly cost us a won game.

I remember many of my blunders vividly. I can often recall the sinking feeling in my stomach and the sleepless night that ensued. To add insult to injury, I remember my blunders far more than I remember the moves of which I am proud. I think many chess players have observed this phenomenon. Perhaps, chess players are simply inherently pessimistic... See?! That was an incredibly pessimistic thought! and I'm a chess player... so there you go...

On a more positive note, I find the blunders of others extremely cathartic. To that end, I'm offering up some of my most painful ones for your enjoyment. These aren't necessarily the dumbest ones I've made. For me, the most painful blunders have a few alliterative factors: stupidity, stakes (was it played in a tournament that mattered?), stature (was it against a player that mattered?), and standing (did I blow a won position?). I've hung plenty of pieces and mates in poor positions or in time trouble, but those don't stick with me nearly as much as the ones that blew a strong position against a strong opponent. I'm offering these positions with minimal commentary - after all I don't want to re-examine these games more than I have to - and I know that some may think the blunders against Simutowe and Langer aren't in the same category as the others, but I must include them because they are the ones that still hurt.

My Absolute Bestest Blunder: Copeland - Nicols

I played this brilliancy in the final round of the 12th grade championships. I had 4 out of 5 which was good for a share of third, I think, and a win would have certainly been good for a top three finish. I was thrilled with the opening, and I felt I was circling a quick knockout, and then... I played the following... My opponent responded immediately, and I just sat there for a couple of minutes before I could gather my thoughts enough to resign. I also had to marinate in the misery of this blunder for a four hour car ride home. Ugggh.

Langer - Copeland

This is not a single blunder, but this game still hurts because I horribly spoiled what up to that point had been one of my best games against one of the higher rated players I had played at that point. I went from +4 to -2 over just a couple of moves.

Copeland - Inuma

This one was at the Denker tournament of state champions. As is often the case with the silliest of blunders, I played this after a long think.

Copeland - Simutowe

Like with my game against Langer, this one hurts more for the fact that I blew a nice game than for the magnitude of the idiocy. I had previously beaten IM Daniel Fernandez in this opening, and I was very happy to catch IM Simutowe in a trick. My position here was completely dominating, and I believe I would have won this game if I hadn't been focused on my opponent's title. I became increasingly nervous about reeling in an IM, and I started to burn alot of time and eventually self-destructed.

Copeland - Pohl

This was my first game against a master. I spent so much time thinking about whether or not I could play Ne2 and allow Qxc4+ and Kb1 that I eventually forgot that I hadn't even played Ne2 yet, and I reached out to play Kb1. I realized my mistake before making the move, but after I touched the king. Unfortunately I was committed, and I resigned without continuing. Technically, I guess the right score would be 16. Resigns?? as Kb1 wasn't played.

What about you? What spectacular blunders have you made that made you question your sanity, intellect, and commitment to chess?