Mathematicians often turn into poets. The joy induced by a mathematical argument often makes a mathematician go beyond theorems and proofs to praise it. I really liked this quote on reductio ad absurdum (proof by contradiction) which I found on Terence Tao’s blog . The existence of infinitely many primes has been proved by Euclid using this technique.

“Reductio ad absurdum, which Euclid loved so much, is one of a mathematician’s finest weapons. It is a far finer gambit than any chess gambit: a chess player may offer the sacrifice of a pawn or even a piece, but a mathematician offers the game ”.
(G.H. Hardy, 1877-1947)