Some quotes from chess players

Many of them may also be applicable to non-chess life :)

"Playing rapid chess, one can lose the habit of concentrating for several hours in serious chess. That is why, if a player has big aims, he should limit his rapid play in favour of serious chess." - Kramnik

"Young players expose themselves to grave risks when they blindly imitate the innovations of masters without themselves first checking all the details and consequences of these innovations." - Alekhine

"Your body has to be in top condition. Your Chess deteriorates as your body does. You can't separate body from mind." - Fischer