Common Chess Errors

The purpose of the following list of chess errors, is to assist us to diagnose our weaknesses when we annotate our games.

Opening Weaknesses
Falling victim to an opening trap
Ignoring the development of your pieces
Waiting too long to castle
Opening inaccuracy
Moving the same piece more than once in the opening

Calculation Weaknesses
Missing the strongest continuation
calculation errors
stopping analysis of a candidate too early
Losing the thread of your analysis (getting lost in your analytical tree of variations)
Retained image error (calculation)
Not analyzing a candidate because it seems to lose material
Stopping the analysis of a line 1-2 ply before the winning move
Not evaluating the position at the end of your analysis

Thought Process Weaknesses
Failing to see your opponents threats
Losing a won game
Losing concentration / Focus / Thread of the game
Not asking the right questions

Time Management Weaknesses
getting into time trouble
playing too fast
playing too slow
Spending too much time on a non-critical move

Endgame Weaknesses
Entering into a lost endgame
Missing a common endgame pattern
Not knowing how to play a fundamental endgame position

Positional Weaknesses
Ignoring your opponents threats
Ignoring King safety
Starting a premature attack
Pawn hunting in the opening
Losing control of an important file or diagonal
Allowing your opponent too much space
Weakening your pawn structure
Misplaying a pawn breakthrough
Entering an exchange which leads to a worse position
Missing a positional move / idea

Psychological Weaknesses
Worrying about ratings / results
Fearing your opponents rating
Playing without a plan

Learning
Not reviewing your games
Learning concepts too advanced for your level
Focusing too much on knowledge and not on skill (studying too much  versus playing too little)