It doesn't require much for ...

It doesn't require much for misfortune to strike in the King's Gambit - one incautious move, and Black can be on the edge of the abyss.
 Anatoly Karpov

Quotes from the same author

Chess is a very tough game, and psychologically a tough game. And of course chess needs a lot of qualities, human qualities. And so you must have very strong nervous system and then you must be well prepared, you must be able to work a lot.
 Anatoly Karpov
Like dogs who sniff each other when meeting, chess players have a ritual at first acquaintance: they sit down to play speed chess.
 Anatoly Karpov
By all means examine the games of the great chess players, but don't swallow them whole. Their games are valuable not for their separate moves, but for their vision of chess, their way of thinking.
 Anatoly Karpov
If the opponent offers keen play I don't object; but in such cases I get less satisfaction, even if I win, than from a game conducted according to all the rules of strategy with its ruthless logic.
 Anatoly Karpov
I still remember Botvinnik's reaction to each of my games, right from the opening moves. At first he would express amazement, then annoyance, and, finally irritation.
 Anatoly Karpov