I think (hope) this is common enough. I've tended to get into particular things - studying how every ear-ring around me moves for a week or two, or fathoming out the varying layer techniques on hair styles, wonderign why that nose looks "ugly" while some other one looks "cute", studying people walking one way or the other. Sadly, with my memory, I forget it all by the time I get home - but that just makes each new day a fresh adventure into "how people work" .