I make the move, and 2 second later I say:
AH SHIT!
How do you feel after you have just made a gross blunder?

That was great - er, horrible, I mean it was horrible to see but a great contribution to this thread.
stwils

normally i say " merda", ou "foda-se" ou "puta que pariu"....and then i try damage control but usually its too big of a f**k up to be controled
I get something like Kasparov in that movie there. LOL
Usually I'm just really upset at myself and then I resolve to do better next time. I try not to let my face show that anything went wrong. When I'm playing OTB, I keep this one, straight face for the entire game. If something goes wrong (even if I'm yelling at myself inside my head) I try not to let my opponent know. Sometimes they think it's just a part of a long combination and so they don't even capture the piece!
If you can put up good resistance after a blunder, you can sometimes save the game. At least you can fight for some kind of draw.
Of course, I try not to make the same mistakes in my next games, but everyone blunders at some point. The winner is the one who makes the next-to-last mistake.

For me it depends on how the game is going on, if the game is very tight and made a wrong move - I feel the temperature around is very Hot but only few seconds and try another move for a remedy.

i am guessing im not the only person, but normally i consider what my opponent is going to play, then i play my "blunder" and then realise that i overlooked a move which my opponent could play and think to myself "i should have seen that one coming". but then i make sure that i consider every option of my opponents next time and try and learn from my mistake

In a speed game, there is that split second where you hope that your opponent doesn't realize your error. Usually they trounce you but I've noticed an interesting phenomenon. Sometimes immediately after I make a blunder, they will counter with one their own. It's worth keeping your eyes open because they may unconsciously relax their game.

I occasionally resign regardless of my chance of winning if I am particularly annoyed at the blunder

Gross blunders always make me feel gross. I usually follow them up by barbecuing a kitten. It's the only thing that I can do that makes that level of self loathing seem justified.
Fantastic
Blunders are part of the game. I make a blunder and lose, I don't mind. I am more mad if I am winning (an OTB game) and time is running out, and I just sit there and can't come up with anything decent that will help me to inch closer to the final victory. I feel strangulated, I feel like a friking salad, staring at the board, helpless. Its a very scary experience.. I also hate when I miss a winning move in an even ( positionally+materially)game. It happened at the Marshall's chess club 3 weeks ago. I was playing this 2000 ELO guy (me apx 1300) and we went toe to toe deep into the middle game, with plenty of time left. You guessed right, I missed a real good move, that would have won the game. It still bothers me, and I know it shouldn't, but I'll get over it....(couple of percocets... )
My first reaction is "I can't believe I did that."
Next I feel embarrassed.
Then I get mad with myself.
Lastly, even though I am feeling bad, I resolve to be more careful, study harder, and try not to let this get me down. (But it still hurts...)
How do you react when you make a gross blunder?
stwils