E/O Challenge: Box. A tag to WIAWSNB, jut because I love that episode
He never should have gone alone; never should have looked for the Djinn without Sam.
It would be something he'd always regret. Not because he'd exposed himself to unnecessary danger (nothing new there), it was because of the things he'd seen; the images that he'd never forget - the wish for a perfect world that had somehow come true.
A world where Sammy still had Jess, their Mom was still alive and he had the normal life he'd always longed for.
And even though the Djinn had conjured a Pandora's Box that would've killed him, Dean had wanted to stay.