Why I like "half-cocked" Jack Shaftoe

Here's an excerpt from the King of the Vagabonds. The scientist-mastermind is talking, just going off on some tangent, in a public square.

"Dyadic, or binary numbers,... ...But what I take away from the Chinese method of fortune-telling is the notion of producing random numbers by the dyadic technique, and by this Winkins's system could be incomprably strengthened." All of which was like the baying of hounds to Jack.
"He's rich," Jack muttered to Eliza...
"Yes - the clothes, the coins..."
"All fakeable."
"How do you know him to be rich, then?"
"In the wilderness, only the most terrible beasts of prey cavort and gambol. Deer and rabbits play no games."

The thing I love here is not only the last line (which is most excellent!), but how endearingly Stephenson makes us like the protagonist. He's all boy, straightforward to a fault: seeming almost a simpleton at times, unconsciously brave, impatient, and deeply perceptive. The guy is admirable, and all the more so because he does not think himself worthy of anything like that. He is earnestly self deprecatory, because he's unconscious of his merits. It's cute.