No, it's not THAT song by Britney Spears.

Sometimes you will cry
   and no one will see your tears;
Sometimes you will laugh
   and no one will see you smile;
Sometimes you will fear
   and no one will see you shudder;
Sometimes you will lie
   and no one will catch you up;
Sometimes you will fall
   and no one will see you struggle;
Sometimes you will be late
   and no one will seem to notice;
But fart just one time...