It's funny how birthday songs are meant to be sung in a loud and boisterous manner, no matter how good a singer you are. Haha just a thought! You've got to announce to the whole world, or whoever is within earshot, that "Hey! It's HIS/HER birthday!" Embarrassing as that may be, it's a classic (Singaporean perhaps?) culture that I enjoy, both as a participant of the singing or as the receiver of the well-wishes. Gives you the sense of warmth and tells you that your friends really love you.