The Power of Vengeance

To be honest I'm not the kind of player that can use my personal dislike of an opponent as a motivating force to play better chess. Sure, if I win the game it makes the victory more satisfying, but during the game I'm mainly concerned about the moves played, not who is playing them. But others I know are able the channel that energy ....
Many years ago a friend of mine was a strong junior player, and was playing in an ACT Championship. Now my friend who I'll simply call David (although I'm sure would be happy if all names were revealed) , was playing a many times ACT Champion. And David was winning. In fact so winning that his opponent (who I'll leave nameless) should have resigned. However in those days we still had adjournments and at the appointed hour the opponent insisted that David seal a move. Why David's opponent insisted on this, when anyone else would have resigned became clear at the resumption. David's opponent was hoping that David (who was still in his early teens at this stage) would seal an ambiguous or illegal move, and therefore he could claim a win. And indeed that is what happened. David failed to differentiate between the 2 rooks that could have moved to the same square, and by the rules of chess lost.
But what annoyed David wasn't the loss, rules being rules after all, but both the circumstances of the loss (ie using the adjournment as the only possible way of winning) and the faux sympathy exhibited by his opponent after the game. So David simply made a vow to beat his opponent in every single game of chess they played thereafter. And he did. Every time they sat down to play David beat him. Long tournaments, short tournaments, lightnings etc David made it his life's mission to defeat his nemesis. Not even a single draw was conceded. The beatings only stopped when David retired from chess in his early 20's. Which must have come as some relief to his opponent.
But there is one final postscript. Despite being out of chess for 5 years or so, David decided to play in a lightning tournament at the ANU, and as it turned out so did his old opponent. So when they were paired with each other, David crushed him once again, just for old times sake.