What do you think really happened at the end of the movie Inception? Have you ever had a dream that you confused with reality?
I think what happened at the end of the movie Inception, is that the writers decided it would be fun to end with an unanswerable question, in order to spark lots of "Was he or wasn't he?" discussions, making sure to leave just enough evidence for both sides that there isn't really an answer anyway.
And that's the point. There isn't an answer and never was. The writers did not decide, when they wrote the thing, which one was true and then resolve not to tell anyone. There just isn't one. It's either one you want it to be. I've decided that I want him to be awake and in the real world, with his real kids, because that's nicer. So he was. Unless you'd rather he wasn't. So quit talking about it already.
Have I ever had a dream I confused with reality? Sure. I imagine everyone has at some point, including the people who, just to be contrary, say they haven't.