If opponent shows cards you can draw conclusions, such as that you could maybe played spot better ?

Yes, it obviously is. 

Here is one example of a spot where I was outplayed a while ago by another regular. This is from 6 max PLO cash game, but the concept should transfer well enough to a tournament.

I was on the river with to weak pairs, some draws had missed, and I checked to opponent who then bet.

Now I could call, fold or raise. 

I thought about it for at least 15 seconds, and came to the conclusion that villain might valuebet two good pairs, some weirdly slowplayed sets (which was basicly nuts), and then probably would bluff a certain % of the times, with his missed draws and other stuff. I figured the range of hands who he would legitimately valuebet was not big enough to counter the times I would expect a regular of his caliber to bluff, so I called.

He showed to (bad) pairs, something like K4xx on AK943, and won the pot. I did not expect him to valuebet that light, and therefore the range that I put him on was wrong, and he probably outplayed me.

I played the hand to my best knowledge, but after the hand was done, I saw that I had flaws in my "best knowledge" of this regular.

preraise AK flop k , pot it flop  pot turn and get shved allin~ think abt it a minute and fold~ to be showed 6 high for total bluff~ ye~ its outplaying i thinks

What you describe Aleks is by no means a given "outplayed spot". If villain only bluffs there 1% of the time, and hero does not have enough equity to call versus villains range on average, hero played it perfectly.

hmm..i was playing that hand with a friend, actually he was playing i was commenting, i said it is excellnt xr spot for lag u gotta call, he said no no..so we actually were arguing on spot, and he folded when opponent showed somethin like 6 high

so i guess he did played it perfectly cause u do agree on fold, my view is that hes been outplayed by making his range face up and playing that hand by too standard playline thats so easy exploitable 

arguments tho are for otehrwise as well, maybe not great example

will try think of otehr example

but rereading posing question , player played it at best of his ability, so its difficult for persn who played its best to say ive been outplayed cause person did best he she it knows, so by default cant comprehend the outplay line

tho i think there re certain spots where we comprehend we made a mistake play line and i think its possible to observe the leak in our own game and what s so good line that opponent made, if we re thinking about game nonstop

I recall is spot i noticed a 2 month ago i think, is certain type of players who wouldnt fold a cbet but float and lead turn, i started noticing play line and took me lil time to adjust to that, by xr the turn lead often by particular player type

its the spot we start to notice we re playing exploitably, we start to observe it and rethink what to do in spot

that moment is moment i think that u can call~ noticing u have been outplayed

This is a silly, albeit interesting question. I'll stand my ground and say that it is obviously possible to observe yourself being outplayed. If I play football versus Ronaldo, and get raped, figuratively speaking, I obviously understand I have been outplayed. This is a physical sport, you might say.

Well, if I play Chess versus Magnus Karlsen, and he has me mated after 15 moves, or whatever number is an appropriate one, I will again obviously understand that I have been outplayed. No matter how hard I "played as best I could". 

It will be the same with poker, unless you are a stubborn 2+2-mongering fool. If villain makes a move you would not suspect him to make (thereby making his actual range differ from his percieved range) and thereby earning him a +EV move, and you a -EV move, you have been outplayed.

With poker even, there is more information to hold after the hand is done, and it should therefore be even more easy to understand what you did wrong, or what he did better. 

Another hand history example:

UTG opens, and I'm on the BTN with A876ds. We are 450bb deep, and I (for some reason) decide to 3bet. He timebanks, and then calls.

Flop A66r. He checks, I cbet and he puts in a small raise. 

Now; I know villain, and he opens tight from UTG, so A66r should not really hit his "calling a 3bet-range" at all. I figure he might do this with some rundowns with a 6 in them, maybe a hand similar to mine, but I also figure he might actually fold some of those hands to my 3bet, since we are so deep, and he has to worry about negative implied odds. And I know he is capable of bluffing, and that this might not be such a bad spot to make a small bluff.

Further, I figure that the best way to make money in this spot is making another min-raise, since I figure calling will look so rediculously strong.

He then pot-raises/or shoves or whatever the potsize will be in this spot, and I figure "well, potsize + my handstrength it can't be a bad call versus the range I have given him".

He then shoves AA45ss, which he preferred to call with preflop, rather then bloating the pot OOP with "marginal" aces, and probably giving his hand away. I did not put AAxx in his range on the flop, no matter how fucking hard or good I tried. His range is therefore totally different than what I thought it was. I can obviously SEE that, since I have eyes, and the cards are right there in front of me. And since I'm not a 2+2-mongering fool, my brain is able to comprehend that he did, in fact, outplay me.

With poker it comes down to ranges, yes, in my opinion. And especially percieved versus actual range. There must be some game between chess and poker (with regards to % of information open), which is a "mind game" which I am not aware of, or which I'm currently forgetting, where my logic also holds water (?).

Perhaps the card-game casino, where my mom used to outplay me when I was young, and I only understood what mistakes I had made, after I had made them, thereby observing myself being outplayed.