Of course you're no spy, dear John - you're a very chivalrous sort, wearing your heart on your sleeve constantly. No, you're made for charging headfirst into battle rather than lurking in the shadows to learn the enemy's secrets - so much so that I'm surprised you're not in Gryffindor.

I also imagine that Sherlock does make it rather trying for you to remain a complacent Hufflepuff? Given his... eccentricities.