"It was all a dream...."

If you watched a TV show for an entire season and then at the beginning of the next season it was revealed that "it was all a dream," how would you feel? Jerked around because it wasn't "real"? Or would you think it was all fictional anyway?
It actually happened with the '70s-'80s show Dallas. An actor whose character had been killed off returned to the show, so they said that season 7 was all a dream.
From a FAQ about the show:

Is it a waste of my time to watch the dream season? Well in many ways yes, it holds no part of the overall plot but there are some wonderful episodes and scenes.

I hope Lost doesn't end up taking some easy way out. (Don't tell me--I'm still watching season three!)