Gabriel wished to be dead, to die in times when Lucifer rebelled against their father. He was almost sure that Michael's thoughts were the same. But they were victorious, came back home from battlefield as heroes, The Host chanted Michael's name like some mantra protecting them from the Fallen. They thought, that tears running through his cheeks were tears of joy. They were wrong.
Through years they were praised as victors, and Gabriel wished for it to last forever.
And then he run, like a coward, away from his family, from his friends, from his love. He hid and became someone else, his mind got darker, his ways became twisted and cruel , he lied and killed in name of vengeance.
Years later, when Apocalypse started for good, he meet those two Winchester boys, and he started questioning himself.
-Why?- he asked looking into unfamiliar eyes in the mirror he was facing.
-Because, my dear- he answered himself hysterically laughing- Because you either die a hero or live long enough to see yourself become a villain...