Common Chess Errors

In his classic Novice Nook The Theory of Chess Improvement Dan Heisman points out the following common chess errors, which I keep running up against.

• Playing too fast or too slow.
• Having bad thought processes – such as playing “Hope Chess”
  (making a move but not analyzing whether you can safely meet any
  forcing reply).
• seeing a good move and not looking for a better one.
• not looking for all your opponent’s threats from his previous move.
• Not following general principles, such as not developing all your
  pieces in the opening or not activating your king quickly enough in the
  endgame.
• Misunderstanding the value of the pieces. For example, thinking that
  trading a rook and pawn for a bishop and knight is usually an equal
  trade.
• Psychological errors, such as not playing with confidence, or avoiding
  higher rated players for fear of losing.
• Analysis errors, like “retained images” (where you analyze and think a
  piece is still on a square from which it moved earlier in the imagined
  sequence) or making “quiescence errors” (stopping your analysis to
  evaluate a position when there are still tactics to be resolved).
• Evaluation errors – thinking a position is good when it is actually bad
  and vice versa.