It was amusing to me to see how the detective's overbearing manner had changed suddenly to that of a child asking questions of its teacher. - Arthur Conan Doyle

The relations between us in those latter days were peculiar. He was a man of habits, narrow and concentrated habits, and I had become one of them. As an institution I was like the violin, the shag tobacco, the old black pipe, the index books, and others perhaps less excusable. When it was a case of active work and a comrade was needed upon whose nerve he could place some reliance, my role was obvious. But apart from this I had uses. I was a whetstone for his mind. I stimulated him. He liked to think aloud in my presence. His remarks could hardly be said to be made to me — many of them would have been as appropriately addressed to his bedstead — but none the less, having formed the habit, it had become in some way helpful that I should register and interject. If I irritated him by a certain methodical slowness in my mentality, that irritation served only to make his own flame-like intuitions and impressions flash up the more vividly and swiftly. Such was my humble role in our alliance.

My dear fellow, you may laugh, but I give you my word that I shall be very glad to have you back safe and sound in Baker Street once more.
- Holmes, to Watson.

We all have neglected opportunities to deplore.