Gabriel was. He didn't know why he was, considering that his part had already been played, but he was. The second thing Gabriel noticed after he realized that he still existed was that he had a view of his Father's creation that none of his brothers in his neck of the woods had ever had. He could see stretched out before him in an infinite number of infinities ALL of his father's Creation. All things that could happen and all things that could be imagined would and did happen, and it was all laid out before him to see.
He instinctively sought the infinitesimally tiny corner of Creation that was most familiar to him and began viewing it as an observer rather than a participant. As the scene played out, he found that his sacrifice had had meaning. Sam had been able to take control of his body long enough to pull Lucifer back into the Pit. In a shocking move, Michael fell with him. A little ways over, a similar scene played out except for the fact that when the door to the Pit closed Michael was sprawled on the ground nearby staring up in the sky in confusion, having been pushed away. In that final instant it had been as if Lucifer had realized his fate and joined Sam in doing all they could to ensure that their brothers didn't share it.
A little further away, he saw universes where the dystopian future that Zachariah had sent Dean Winchester to had played out almost exactly as Dean had seen it. A little ways away, a universe that was like those caught his eye. The main difference between it and the universes he'd been looking at moments before, was the timing and manner of Castiel's death. He didn't know why this had affected him so. Before Castiel had brought himself to his attention by being a minor annoyance, he hadn't even really known the angel. Afterwards, the slowly falling soldier who had watched his faith in his brothers and their father be crushed had grown on him a bit.
Part of him was crying that Castiel - his younger brother who had given everything he could to stop his brothers and sisters from destroying their father's creation even when it meant rebelling against his orders and falling - didn't deserve this. Castiel should be reveling in his newly restored grace and experimenting with his new powers like he was just a little ways over, not dead in a ditch after a drug overdose.
As he watched the members of the small camp dump in the rest of the day's dead which included a Dean Winchester who had been killed by a Croat that Castiel should have been there to save him from in preparation for salting and burning the remains, he found himself burning with a desire to do something about this.
Suddenly, he knew that he could do something, and how it was possible to do so. As he headed to a point on the timeline, he found a gentle force batting him away towards a point that was much further in the future than he had planned. It would seem that certain things were meant to be, but there were certain things he could still change. When he reached a point on the timeline that wasn't forbidden, he moved in closer searching for what he needed. He soon found it.
Merging with his counterpart was very easy. While there were an infinite number of Gabriels, there was something at their core that made them one, as if they were infinite aspects of the same being. As both aspects were nearly identical, as opposed to say he and that total asshat with the trumpet he had caught a glimpse of elsewhere when he had been looking at all of creation, the transition wasn't very jarring.
One thing about both of these aspects of Gabriel was that they were both pranksters. The newly merged aspect of Gabriel was no different. As he mused over his next move, he knew that when he made the change needed to prevent Castiel from ending up dead in a ditch, he would make it both spectacular and entertaining as hell. He would also be doing something to light a fire under the Winchesters to get them to deal with the Apocalypse sooner rather than later, since there would be no point in keeping Castiel out of a ditch if it meant he'd be killed by Lucifer instead.
That sounded like an awful lot of effort on his part however. While he wasn't exactly lazy, he didn't plan on going all over creation announcing his presence to those from whom he'd been hiding while babysitting Castiel and simultaneously stopping the Apocalypse, especially since he'd originally run and hid so he wouldn't have to choose between his brothers when the time came. If he could just set up something self-sustaining that would both make Castiel take better care of his vessel and motivate the Winchesters at the same time with minimal effort on his part, he'd be set.
What motivated the Winchesters though?
They were almost fanatically obsessed with family...they were...they were...
Gabriel didn't bother to suppress the diabolical grin or the maniacal laughter. He just had the perfect idea.
