Sometimes when there is a lull in the game, when he's given the rare opportunity to relax and worry less, John likes to think about Karkat.
Karkat is an interesting individual that comes from a different planet –a different universe, even— so of course there's much to ponder, but what John is most curious about is what he looks like. He's long since abandoned the notion of them being human, so it's only natural for him to wonder.
He vaguely remembers the first full conversation he had with Karkat. It seems so long ago. How long has it been? Weeks? Months? Years? He can't recall too much of it, but he does remember Karkat calling Jade ugly. Since then he's made many comments about human aesthetics, actually.
Bone bulges, thinkpans, horns… it doesn't create much of an image. Well, not one that isn't extremely weird. When he thinks of trolls the only thing John can imagine are those nightmarish little dolls from his childhood with obscenely large noses, wild neon hair, and stumpy little naked bodies. It's not too much of a stretch to think the Alternian trolls look like that, right? It seems plausible. Maybe they created the freaky little figures in their image so they could show humans what "superior anatomy" is.
And so, John pictures the creepy trolls with large heads and shrunken bodies donning horns, a pan on their heads, and a bony appendage protruding from somewhere and is more than a little appalled by the imagery. He wouldn't care if Karkat looked like that, though, not really. Even with an odd appearance, it would still be Karkat.
It is at this point that John will be pestered by one of his human friends or even Karkat himself, alerting him of some critical matter and that he better "GET YOUR USELESS HUMAN ASS UP AND FUCKING DO SHIT, NOT LAY AROUND LIKE A MOUND OF FUCKING HOOFBEAST EXCREMENT".
John does indeed get his human ass up, dusting off the dirt from his trousers, and continues to forge a path toward their goal.
He can't wait for the day he can finally meet Karkat Vantas.