The skill in poker has to do with understanding the nature of random events and being able to devise winning strategies in an environment run by random processes.
That quote is from a strategy column by Tony Guerrera that appeared in the July 20, 2009 edition of Poker Player Newspaper. Check out the full column here. I think the rest of the column other than the above quote has a good general observation about elements of strategy necessary for playing against tough opponents, but when I read the quote above I really thought that totally crystallized what it means to be a good poker player.
Understanding the Nature of Random Events - This is probably one of the most difficult things to do as a poker player. It is ingrained in our brains through non-poker activities that doing the "right" thing, making a "correct" choice should lead to a positive result. Poker turns that on its ear because there really is no direct correlation between making good decisions and getting good immediate results. How can this be though? Aren't we 'entitled" to be rewarded for our good decisions? Not as poker players and the reason is - randomness. All we can hope to do as poker players is make decisions that will lead to a good result most of the time. A fair amount of the time too the edge that you are going to have is something like 60/40, so even though it will work out most of the time the times that the result will be good aren't that much more frequent than the times that the results will be bad. So that's the first hurdle you have to overcome in understanding randomness; realizing that you'll do the right thing and lose - a lot.
So surely after you've come to grips with that fact you understand randomness right? I mean, I've come to grips with the fact that I can make the right decision and frequently lose, that's enough isn't it? Oh no my friend, mon ami, mi amigo - you're just getting started. Why, because the true nature of randomness lies not in the fact that in the long run, result A will occur X% of the time and result B will occur 100-X% of the time. That's really just understanding probability. To understand randomness, you have to understand that every time a card flips over the unlikely result has a non-zero chance of occurring and it doesn't what matter one bit what happened the last 3, 10, 100 or 10,000 times - when that card flips over there's absolutely no reason why the unlikely result cannot occur again. In other words, no matter how big your edge, you haven't won the hand until all the cards are flipped over.
Now as my poker playing has progressed I've gotten better at understanding the nature of random events, but I'm still not all the way there. I'm going to keep working on it though - that and, of ocurse the whole "devising winning strategies" part of poker skill.