restaurants with silly stupid birthday songs

Why do restaurants feel the need to gang up on birthday people and sing a stupid chant? The only thing I can see good about it is that the waiters and waitresses get a break in doing their real job, waiting on people. It is annoying. You are having a quiet dinner with your spouse/friend/lover and all of a sudden a herd of wait staff come toward you clapping and singing off key and getting louder and louder. You think to yourself. Is it my birthday? Why are they making so much noise? Does anyone really like to have all the employees in the restaurant sing a stupid song for their birthday? Most people I know would rather have a tooth pulled than to have this singfest at their table. Give me the free dessert and skip the annoying overture.