Despite relying heavily on Meg as of late, Castiel had been trying to prove to himself that he was capable of being self sufficient enough to spend time alone in his apartment. He didn't attempt anything too adventurous when it came to food stuffs, just made enough sandwiches that he was sure Dean would look at with disdain, because it paled in comparison to any of the sandwiches he'd seen the hunter eat. He'd busied himself with trying to check out the various items in the apartment, books and other assorted things, because he needed to pass the time. Television could only keep him occupied for so long, considering the sort of entertainment value that a lot of the programs he came across actually had.
Later on, Castiel decided he needed to press out on his own. He'd been paid a visit by the Winchesters and they were the first, aside from Meg, he'd come in contact with. He told himself he was going to try and meet new people, despite that inner apprehension that he didn't know what sort of people he might be facing and he didn't have the abilities of an angel any longer. He couldn't protect himself as he once was able and that was proof he needed to be careful.
So he wore his trench coat, as a security blanket against not just the world around him, but also his own inner fears that he would run into those who might be a threat to him. He no longer looked like he was sad and broken down, his shoulders not slumping. He didn't walk with purpose, didn't stride along like he was unstoppable, but he didn't try to blend in with the rest of the world, either.
His walk (walking was strange for him, because he'd been so used to going from place to place in the blink of an eye), it did not lead him into town to try and get to know others who were stuck like he was. Instead, he found himself at Meg's home and while she had knocked time and time again to get into his apartment, he went wandering around, to find an entrance that would let him inside.
And he saw something that both left him confused and aroused.