We had a similar story in one of my campaigns recently. The party had a Deva Psion, Galad, whom we'd all humorously called Chaotic Rude because even though he was good, he was a jerk. He'd walked the line between evil and good for a while, and finally he and several other players caused a mutiny on a ship and scared the captain into leaving. That night, in a dream, he was told he'd reincarnate as a Rakshasa if he died... and he accepted! He fled the party to the city, grabbed some supplies, and the returned, telling them he'd repent and save himself from that fate. Later, he turned around, locked them in a building, and tried to kill them! He failed, but it was a good lay of character, he seemed to just be being good because of his party members, and when given the chance to be evil, took it. It was a cool end to our campaign.
And I myself have felt sad and angry while playing games, I won't spoil it, but I failed to do something at the end of Mass Effect 2. I was infuriated and attacked with rage until the end. It was... intense.