Sherlock: Sentiment is a chemical defect found in the losing side.

Irene Adler: Sentiment? What are you talking about?

Sherlock: You.

Irene Adler: Oh dear God. Look at the poor man. You don’t actually think I was interested in you? Why? Because you’re the great Sherlock Holmes, the clever detective in the funny hat?

Sherlock: No… because I took your pulse. Elevated… Your pupils dilated. I imagine John Watson thinks love’s a mystery to me, but the chemistry is incredibly simple and very destructive. When we first met, you told me that a disguise is always a self portrait, how true of you, the combination to your safe – your measurements.  But this, this is far more intimate. This is your heart, and you should never let it rule your head. You could have chosen any random number and walked out of here today with everything you worked for. But you just couldn’t resist it, could you? I’ve always assumed that love is a dangerous disadvantage. Thank you for the final proof.

Irene Adler: Everything I said. It’s not real. I was just playing the game.

Sherlock: I know. And this is just losing.