Despite the fact that Jonah and Seth were currently having their differences (the overall number of fingers they should have, for instance), Seth was still the person Jonah had spent the vast majority of his time with for his entire life, and so his looks and mannerisms were easy to adopt. The cast of blistering disdain was one of those; it didn't come as easily to Jonah, but Seth could lacerate a person just by looking at him.
"It's my blood sugar," he ....lied, blithely, of what exactly was off about him, and like Seth he could manage to extend the impression that he wasn't concealing the lie because he just couldn't be bothered. "That's where I'm going. I'm not sure how that's relevant to you, exactly. You don't like us. That's pretty obvious."
A beat. "Please get that thing out of my face. It's rude."