[ That's another thing, to see people actually go to the library to read. It's mostly been used as a place to mingle with anything but the books - it's why he avoids it. Hannibal is reading up, and while it isn't entirely uncommon it is still more strange than anything. The lack of a notepad is something that catches Sherlock because it can in fact imply two things leisure or a good memory. Either one is alarming. If leisure was the case, consider he's taking up more scientific texts it implies a scientific mind behind it. Good memory is another thing that catches him because the amount of information available in those books and he's not taking a single thing down?

The smile piques Sherlock's interest.

Sherlock takes a moment to read into the wording. He doesn't identify it as modern, he notes the hint of formality almost. ]

That's because books don't stimulate most people. People prefer their information and condensed and bullet pointed, a result of technological advancements.

[ It also implies he's a regular at a library. ]

Not you, though.

[ addressing his choice of reading material. ]