"There are two types of sacrifices: correct ones and mine" -Mikhail Tal
// courtesy of http://www.chess-poster.com/english/notes_and_facts/chess_quotes.htm
// and other various sources
Thanks for the info @MrCharles
Some witty quotes in there :D
"When you absolutely don't know anymore what to do, it's time to panic" -John van der Wiel
"a pawn is a pawn"
"Chess sucks" -Patralgan
"I don't believe in fortresses" - Magnus Carlsen
"When in doubt play a4."
"If in doubt, castle. If not, castle anyway". I can't remember where that's from but I like it.
"If you retreat from chess tournaments and start to think to chess like a fun,of course you get improve" from a chess player in peace with the world and himself.