Actually, It is only common in the (spoiled) western world that you move out, if you just go to south of Europe, things are different, not because of culture (which isnt THAT different), but because of the housing problem - there aren't enough houses. Also, in countries where they do not have much money it is also common to share roof with your parents and take over as "breadwinner" for the family when they get older.
Now when the global recession hit us hard too, maby attitudes will change to the better.
I can say this about how i feel: i dated this girl last year that complained about dates she had that live with their parents, for me - that pretty much summed her up, i quickly labeled her as an unempathic ass, and we never saw eachother again, she wanted to be a "friend" to me, but i couldn't stand the sight her.
What goes around, comes around.
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"It is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring" (Carl Sagan)