My parents had a sense of humor, but only after we were all grown up...and we were all Favorites, but I was really the only Favorite because my dad told me...
I told both of my daughters they were my favorite. When one of them said that I told the other the same thing, I would tell her yes, but that is so I don't hurt the other's feelings, and you are really my favorite b/c (list off the traits specific to her that were her character strengths or made her special).