Alone. Isolated. Solitary. No-one around to listen to him. Just to talk, that's all he wanted. But there was no-one he could talk to. It was strange. He led an army of angels. Castiel was constantly around people, around angels in the dozens, but as a leader to the angels, and a random guy to the humans. No-one bothered to talk to him, to ask him how he was faring. No-one wanted to. They wanted a lot from him, but gave little in return. But that was his life.
He could give almost any order, and his angel army would carry it out without question. But they were only interested in restoring order to heaven, and none cared about him at all, except that he lead them. Sometimes, he felt like reaching out, just to touch the angel in front of him, make it notice that he was there, but alas, loneliness was not an excuse to break down, and so many angels were counting on him.
It was also strange to be around Sam and Dean. He helped them constantly, and they were always complaining, and he'd listen. But they too never asked if he was alright. They wouldn't listen or care if he started on about feeling like he was about to crack under the weight of all this responsibility. Of course, he was used to responsibility, but having all this hoisted on him, so much with no notice, it was difficult. But, he couldn't tell them that because they wouldn't listen. Could he blame them? Sam didn't have a soul until recently, so they had had their own problems. Nevertheless, a small bit of Castiel wanted to smite them for their inconsideration.
He watched people below in his spare time. They'd go to work, but when they came home, there would be a smiling child, or a loving partner to greet them. He didn't have any family. No-one who listened to him. Gabriel and Anna, his siblings who he'd gotten to know fairly well were dead, and his father, God, had long since abandoned them. No, no help from family. Or friends.
That left no-one, he supposed. No-one around, and a great weight on his shoulders. But there wasn't enough time to mope about that either. Too much to do. Run a war, save Dean and Sam's asses on occasion, and track down lost angelic artifacts. And no close help. No kind words or friendly advice. But that's the way it is, and he supposed that it probably wouldn't change for a while. So he might as well get used to it.
I was feeling rather lonely today, and decided that Castiel knew the emotion fairly well and I'd relieve my boredom and loneliness by writing this. Poor Cas.