What would you think if you walked into a public restroom and every person standing at a hand wash basin was singing the HAPPY BIRTHDAY song? All were singing at different points of the song. Some were beginning and some were ending. After you finish your business you too would go over and start your Happy Birthday song. I guess some would really put their hearts in their singing and some will sing in drudgery.
The other days on the news one newscaster asked the other how long should you was your hands? As long as it takes to sing the Happy Birthday song.
Of course, while scrubbing down doctors and nurses might want to add a few more verses or maybe even make wishes.