BE OBJECTIVE – PLAY THE BOARD AND NOT YOUR OPPONENT!
Sometimes. they give their opponents too much credit because of titles and ratings. Sometimes, it is reversed and they completely underestimated their opponents because of ratings. This even happens to grandmasters on countless occasions.
Here are a few examples:
Example 1: GM Klaus Darga vs GM Levente Lengyel
In this position, White resigned in a winning position after 41…R6xe2. Too much respect for his opponent. He could not imagine that his opponent could make a horrendous blunder. He assumed that after 42. Rxe2 Bxh4+ wins without realizing that 43. Ke3 +-
Example 2: GM Veselin Topalov vs GM Vladimir Kramnik
These 2 players hate each other. This game was from the World Championship match. Black’s position was completely hopeless. But personal hatred clouded clear judgment. A simple 32. Rxg4+ Bg7 33. Qc7 and black has no defenses. White lost all composure and went on to lose this game and match 8.5-7.5.
Example 3: GM Alonso Zapata vs GM Viswanathan Anand
In this game, Anand, one of the greatest players in modern chess history, resigned after 6. Qe2! This can be a case of underestimating a much lower rated opponent.
So the lesson is to play the game you have in front of you, and not let your opponent affect your game, no matter if he/she is higher or lower rated. Stay focus and do your job.