Anything is better than stagnation.

Before turning to those moral and mental aspects of the matter which present the greatest difficulties, let the inquirer begin by mastering more elementary problems.

My mind rebels at stagnation. Give me problems, give me work, give me the most abstruse cryptogram, or the most intricate analysis, and I am in my own proper atmosphere. But I abhor the dull routine of existence. I crave for mental exaltation.

I wanted to end the world but,I'll settle for ending yours.

I say, Watson,’ he whispered, ‘would you be afraid to sleep in the same room as a lunatic, a man with softening of the brain, an idiot whose mind has lost its grip?’ ‘Not in the least,’ I answered in astonishment. ‘Ah, that’s lucky,’ he said, and not another word would he utter that night.

There is nothing more stimulating than a case where everything goes against you.

I am a brain, Watson. The rest of me is a mere appendix.