Trying to do the right thing did not always equate to doing the right thing. That was something that Castiel had learned the hard way -- more than once. But Sam, even this Sam, seemed to get it. And that was the thing that Castiel liked about Sam in any form -- one of the reasons he liked the younger Winchester so well. They were very similar in some regards, and Sam was, ultimately, more forgiving than Dean.
Which was probably why Castiel wasn't amazingly hesitant about telling her what had happened. His outline was terse, because he was terse and also because if he went into every little detail they would be here all night. While Castiel had no large interest in going back to his rooms, the scents of the cafeteria on his new human nose was getting to be a bit much. He just didn't know what to focus on.
So he started with after the apocalypse, focusing on what he felt was most important: the war in heaven against Raphael, building an army. His attempts to keep Sam and Dean out of it, and how it was a mistake, particularly once he'd started looking for souls. Searching for Purgatory, working with Crowley.
"I'd become god," he said, refusing to look at Sam for that, he was still more ashamed than he could even vocalize. "But I couldn't… it tore me apart." And then there was breaking Sam. His own death and subsequent rebirth. The Leviathans and taking Sam's hallucinations -- losing his mind for the effort. Defeating Dick Roman. Purgatory.
He paused just to eat more soup because apparently when humans talked for a long period of time, it made their throats go dry. Even the condensed version was long -- three plus years was a lot to cover.
"And then -- there were trials. To close Hell. That's what my Sam and Dean were working on. I thought I was doing similarly with Heaven, but it wasn't the case."