Not really but then I never really have... It's an unusual quirk I have along with seriously disliking anyone who greets another person just because they walk past them in the street, it's not polite, it's a gross invasion of privacy! (I may have issues...).
I reckon I'd take note if George Clooney walked in to the room though... I'm unobservant and anti social, not dead fvrom the waist down :c)