exactly how do i figure out my biggest weakness? Identifying it seems to be difficult in itself.

 Why wouldn't you work on eliminating your weaknesses? Makes no sense to me.

Opeings are my weak point.  well, the weakest among all of my weak points.

My biggest weakness is that I dont know much about creating and keeping advantages in the mid game. My wins are based on spotting tactical blunders and more or less fortunate development of things, but once every piece is developed I am usually a little bit clueless about how to go on, especially if the position is still balanced.

So if anyone knows a good resource on how to get better at that I'd be happy to hear it.

if a player can improve within few days and can remember all of his/her game...is he or she very talented?

 I have thought about it, but I can't figure out any weakness.  The only thing I can come up with is that if I have a slight advantage I find it difficult for me to make it grow against players around my rating over the board when they play solidly.  Any ideas how to improve this situation?

Quite honestly I couldn't agree more.  I believe if honest introspection (and just plain being objective about your wins/losses in general) and desire to improve were more common the average ability of chess players in general would be the equivalent of many hundreds of points higher.

Too often you see as in this thread "Why should I" and everywhere else you see "look at my amazing win! (please neglect the errors and critical moments on both sides)"

 Gather a bunch of games where you lost now ask yourself why did I lose or what phase of the game do I keep seeing a pattern of uncomfortable positions. If you haven't been losing at all do the same with your drawn games. If you've just been winning a lot play higher opposition and let them test your skills and jsut keep repeating.

It's true. Weaknesses really drag you down, and are the most depressing to improve on, because your lack of proficiency in some area may disgust you. But if you buckle down and realize the necessity of shoring up your weakness and honestly criticizing your problems, then you are taking huge steps to actually get rid of them.

Too often I would just study what came most naturally to me, but that didn't get rid of the losses I was getting from missing easy forks and checks.

If you have a weakness in tactics (most common), then it can be especially annoying because that means at any point, even if you go 40 moves with no blunders, if you blunder afterwards the hard work is wasted. Or if your endgames really suck, and you're in time pressure, you may fail to win with the extra pawn you so elegantly forced him to give up -- perhaps due to strong positional play.

I think it's more important to lack obvious weaknesses in your play than to sometimes play brilliant moves but often later on in those same games make some serious, often remarkably simple, yet overlooked, mistakes.

I think the most progress I have ever made for improvement has come from the sheer realization and submission to the inevitable necessity to augment and critique the weak points of my game.

Okay I wanna have this religious experience How do I do this? Where can I listen to Josh go over his own games on Chessmaster? Do I have to buy something? Chessmaster? Is there a link?

Dealing with tons of weaknesses, though the scariest is currently handwaving! 

NM Heisman refers to this as playing "superficially" or just playing to general principles instead of rolling up your sleeves and thoroughly analyzing critical positions when they occur.

It's good to be able to identify critical (highly analytical) positions and slam the brakes. It takes more discipline to grind into them ... calculating forcing lines till quiescence when necessary! This is something I need to really work on.

Too many of you people are way too eager to improve. Who will be left for me to defeat?