There are moves that we play that seem the most natural in the world, but tactically they aren't justified. It is very annoying when this happens. Things like:
- retreating an attacked piece
Unless the move is absolutely forced, then moves shouldn't be played automatically. We all miss things, but it is most annoying when we miss something that we should see.
I feel for the player in this example:
This game, from an Austrian League game last week saw white commit 2 mistakes over the one move.
First, he played a move which looks natural without checking the situation on the board.
Second, he didn't look at all the checks and captures in the position.
White played the seemingly natural 15.0-0.
Now if white had been thinking about checks and captures, he would have noticed 15..Bxc4 and should have considered that move.
White resigned in this position. Here, it is obvious that black's queen is coming to d4 to check and fork white's bishop which will be on c4.
Moral of the story is to check natural looking moves. Even better is to get the thought about natural looking moves out of your head, and take positions on their merit. I think capturing and recapturing is the biggest area where most club players could improve.