Originally, the plan was for Sam to use his developing psychic powers to save Dean from his crossroads deal. Because the strike cut the season short, there wasn't enough time to develop Sam’s "dark side" convincingly. The writers were forced to let Dean actually go to Hell in the finale, No Rest for the Wicked .
This forced ending paved the way for Season 4’s introduction of Castiel , who was needed to "raise Dean from perdition". Without the strike shortening Season 3, the show might never have introduced angels, a move that redefined the series for the next decade. Hidden Gems in the DVD/Blu-ray Pack Supernatural Season 3 Complete Pack
The Official Season 3 DVD includes featurettes where creator Eric Kripke and writers discuss the making of fan-favorite episodes like Mystery Spot and A Very Supernatural Christmas . Originally, the plan was for Sam to use