What is the biggest blunder you made during speed chess?

I was playing speed chess with a 1 second per move mutally agreed speed (no clocks). I'm about 1430 and was playing someone who is about 900. I won obviously, but at least 3 times during the game I failed to capture a piece that was just left hanging. Sounds normal, right? Well then I stepped my king into check twice, one time during the endgame to capture a pawn that was guarded by the other king! The other 900 players, watching, said, "hey, you can't do that". Mistakes like that really made me wonder if I've gotten stupider suddenly. Are my mistakes normal?

I've had so many blunders in speed chess. Many of them turned the game from definitely winning for me, to immediate resignation from me.

The biggest blunder I've made during speed chess was asking my opponent's wife out for a casual roll in the hay after the game. The only upside was getting a lot of opening and endgame study done during the ensuing hospital stay.

I just hope my blunders were the result of me not playing in over a month. I was probably about 1250 before I started studying books. Then I climbed to 1450 for about 2 months. Then I decided the addiction was bad, and stopped playing for at least a month. Then I started playing my roommates again and was amazed how much better they are doing against me. I think Class C chess skill has a lot to do with how familiar you are with the game. If you stop practicing, you start missing obvious stuff. Still, stepping my king into check seemed very excessive. I still wonder if I'm getting dumber over all.

There isn't a speed chess game played by me without blunders. I can't name the worst one, as this would be missing a mate in one or hanging the queen, and I've done both countless times. However as you've pointed out, the real embarassing thing is when I play OTB and don't even notice illegal moves (moving out of an absolute pin, etc.)

Losing the white bishop on g5 to a check by black queen on a5. Extra careful about this tactic now.

Anyone rated at least 1400 who made illegal moves during a bullet game? Anyone notice that a king was in check for at least the last 4 moves?