When I first started playing, it eventually dawned on me that there were only two gears to play chess: Try your best or resign. For a critical tale of how I reached that conclusion, please refer to The Train Story.
Today I would like to relate another story of how dramatic that difference can be between a 2200+ player and a class player, in this case two 1700's.
About 15 years ago I was watching a game in the U1800 Section of the World Open, which was then held at the Adam's Mark Hotel, about 3 miles down the road from my home.
I did not know either of the players I was watching. They were both about college age and rated about 1700. The round had been going on for more than four hours, so they were in the second time control (40/2; SD/1), let's say move 44. Both had about 50 minutes left to complete the game. They had reached a king and pawn endgame where one side was up a pawn; I think it was Black. Let's say Black had five pawns and White had four. If I remember correctly, Black had the more active king but White had some compensating advantages in the pawn structure.
It was a pretty difficult position; it looked at first glance that Black should win (as is usual in king and pawn endgames ahead a pawn and with many pawns on the board) but it wasn't trivially easy.
First I looked at the plan where Black would bring his king to the queenside and attack the b-pawn. Passive defense by White was clearly hopeless so he would have to make it a race by bringing his king to the kingside. I counted the race and apparently both sides would queen, but Black would remain a pawn ahead in a queen and pawn endgame.
Then I calculated what would happen if the black king stayed on the kingside. Again that was murky as it would not be easy to create a winning passed pawn, due to the pawn structure. It was not easy to calculate exactly what would happen. Even if I could calculate what the eventual stability of the kingside would be in that line, Black's work would not be done, as he would have to calculate whether staying kingside first and then later trying to go queenside was better than just going queenside right away. There were several possible alternatives; too much for me to calculate in a few minutes. I still felt that with careful play Black was probably winning.
While I was calculating Black's 44th move, an amazing thing happened: the players both played many moves extremely quickly and White resigned! Black had immediately moved his king to the queenside and White's monarch had hopelessly followed, resulting in inevitable defeat.
After the game I asked the players if they would like to review the game with me in the Skittles room. They accepted and, when we got there, I introduced myself as a master and asked them to set up the position on the 44th move, which they gladly did, happy to get some masterly help.
I then proceeded to show them my analysis: why immediately brining Black's king to the queenside (as in the game) was problematic and how White could also queen in that race. But I also showed them that the other lines were not immediately decisive, either, and that it was going to take some effort for Black to force a win.
Obviously both players were relatively careful and slow: both had taken about 130 minutes for their first 43 moves. So then I submitted the question I had been waiting to ask:
"You guys are apparently careful because you both used over 2 hours, but how could you play out such a critical king and pawn endgame so fast? After all, the decision of what to do on move 44 was not at all easy and I was unable to come to a clear decision just about that move - while you were playing out the entire remainder of the game!"
Black's answer: "I thought I was winning and that it was trivial so I just played it quickly, expecting to win."
White's answer: "At that point I thought I was dead lost but, rather than resign, I thought I would play a few moves quickly just to see what would happen."
Very reasonable and understandable answers, but not ones you would get from many extremely strong players. The 1700 players were using a gear I just don't have: play fast and see what happens. My only two gears are 1)Take your time and try your best on every move or 2)resign. If they had taken their time, they might have realized the position was not so clear or easy as they thought it was; for example, maybe with some care White could have drawn against the line Black quickly chose.
Bottom line: If you want to know one difference between many 1700 players and most 2200 players, this story is worth remembering...