When you think about all the screaming girls and scenes he probably has witnessed in his life this is kind of a role reversal!   Paul McCartney was captured on video with, "ME! ME! ME!" running through his head.   Paul was trying to catch a souvenir in Brooklyn.  He could probably buy several thousand if not million of these T-shirts if he wanted to.   It looks to me as if he is simply having a wonderful Christmas time!