People are not that interesting between the beginning and the end of their lives, they're only interesting toward the beginning and toward the end. So it's weird for someone to have an everyday interest in someone else, it's weird because they're usually gathering intel or counter intel on the person they claim to have an interest in, rather than minding their business.
The guy wasnt interesting, and yet the other person claimed to have an interest in something he was doing, so he had to wonder what agency sent the other person. There are no victims in the spy community, spies get paid for their work, not forced into their work.
(adj) 1. Capable of holding one's attention; 2. Arousing a feeling of interest; 3. Oh god oh god, we're all gonna die
"this landing is gonna get pretty interesting."
"Define interesting."
"Oh god oh god, we're all gonna die?"
"This is the captain. We have a little problem with our entry sequence, so we might experience some slight turbulence and then... explode."
Defined as something you say after someone says a phrase that you disagree with but don't have any counter argumentso you say "Interesting" to make it seem like they are in the wrong.