Last week William Jensen wrote an article putting the five biggest mistakes that he's ever made in a match on display. Some would say that it's not very productive to dwell on errors, but I'm inclined to believe that Huey became so great at the game in part by realizing that he was capable of pedestrian boneheadery, and using this to motivate himself to be better.
This article got me thinking about some of the bigger errors that I've made in matches. I Spell Pierced a Daze one time, and that's certainly one of the more humbling stories of my life, but there are two that come to mind that are far more compelling.
When the GP format in Minneapolis was Modern I was 6-1 playing Izzet Delver and I was paired against Merfolk. I won game one and was in great position for game two, with a Vedalken Shackles in play and a Lightning Bolt in hand. I was, however, at three and my opponent controlled a Master of Waves and a Mutavault. I drew a second Vedalken Shackles on my turn, and with five mana I had the ability to cast it and activate one Shackles. If I were playing for a long game, this play might have made sense as I would be getting the Shackles in under a counterspell. This game, however, would end the next turn. My opponent drew and played Lord of Atlantis and by playing the second Shackles I was unable to interact with two Islandwalking threats. It just didn't make any sense to play a second Shackles while the first was untapped, and I lost this game and later the match because of it.
The other big mistake that comes to mind stands out largely because of how I threw away a tournament when the deck I had designed was one of the best that I had ever brought to the table.
With an early game that consisted of copying whatever your opponent was doing or outright countering it while you gained incremental card advantage and Vapor Snagged or Dismembered whatever they were trying to do, and a late game that consisted of an endless stream of Wurmcoil Engines, this deck was a thing of beauty. The big downside was that the deck was often incredibly hard to play.
My big mistake with this deck came against Naya Pod. My opponent had just Podded into a Zealous Conscripts, and it was getting to be do or die time on my side of the table. On my turn I played a Phrexian Metamorph, copied the Conscripts and stole the Birthing Pod, using it to Pod into a Wurmcoil Engine. This was a pretty solid position, except I forgot one thing... I neglected to sacrifice my opponent's Birthing Pod to Phyrexia's Core. Things spun out of control from there as they tend to do when you face down an active Pod, and I lost. It was only round two or three or an SCG Open, but with how good this deck was I had let myself down probably more than any other match I have ever played.
These mistakes and others weight on me sometimes, but the most important thing is to use them as teaching tools, not reasons to get down on yourself.
So what's the biggest Magic mistake you've ever made?