Sirius got up and very nearly threw himself at Remus when he appeared, before he remembered that Remus might still be sore from the full, and he held himself back from doing so; if he'd been a less graceful man, he would've fallen flat on his face, but he managed to catch himself and hovered a little too close instead. "The flat?" he asked, worried that Remus was upset about the mess they'd made (he knew he should've thrown away the pizza boxes!)
Of course then he realised Remus was probably talking about the situation - the one with the homicidal werewolf, the kidnapping of children, the madness within the Order - and figured that pizza boxes were the last of his problems, obsessively tidy or not.
"Oh," he said, deflating a little. "Yeah. One big fucking mess." He felt a hot rush of guilt, an emotion he wasn't used to feeling, and it made his stomach lurch horribly. If he hadn't talked to Greyback, maybe they could've prevented this from happening. Then Remus wouldn't have had been traded - traded! - to Greyback. Given over like that. And now the Order was up in arms, and Remus was in the centre of it, and it wasn't bloody fair.