Not-California Dreamin'

Many of my dreams have taken place in the house where I grew up, never in my condo, and only once so far in the house where I currently live with my mom.  I've pondered why that would be, although I'll admit I haven't pondered it very much.

I just finished Agatha Christie's autobiography, and she suggested the following reason.  It is always Ashfield, the old familiar setting where one's life first functioned, even though the people in the dream are the people of today.  How well I knew every detail there...  Now why didn't I think of that?