In a roundabout way, Castiel was used to dealing with others who were prickly in nature or never quite put themselves out there as honestly and unabashedly as he did. The Winchesters had issues in trusting others, in looking toward anyone but one another for things, because of how often they'd been let down. Even those close to them were often sold short because of their views and that was something he'd called Dean out on, in the past. With Meg, she'd trusted him to fall asleep at his apartment and stay there for a period of time, but she left not long after the next morning, that being the last he'd seen of her. He liked hearing from her, knowing she was safe, but he also had gotten so used to seeing her every day that not seeing her for a change was different for him.
"I wanted to," he informed her, not realizing she probably already knew. She was sitting on her bed and he was standing there, awkwardly trying to look like he wasn't out of place in her bedroom. He knew she didn't sleep, so there was a part of him that questioned why she had a bedroom in the first place. But, homes typically came with amenities that demons and even angels, back when he was one, had no use for.
"And I have not burned down my home. It is still standing." He reassured her, letting her know that she'd left him and he was able to take care of himself, like she asked him about just nights prior, for when she wouldn't be around. There was a beat, as he felt like he should have gotten a message off to her first, before showing up. "Is my presence upsetting to you, Meg? Would...you like for me to leave?" He didn't want to be here if it upset her to have him here, because he got in the way. Because she had to look after him so often and he didn't want to be that burden to her.