... because mommies aren't as good at making beat-box noises while making babies "dance".
... because mommies might not think of making fart noises and pretending that they propel a baby into the air from the force of the gusts.
... because mommies forget that bath time is, first and foremost, time for blowing raspberries on naked baby skin.
... because mommies may not notice that a red-and-white polka-dotted shirt looks something like a bandanna. Therefore, they might also not wrap it around a baby's head (and one of her eyes) and swish her hand around while growling, "Avast, ye mateys!"
... because mommies get so caught up in feeding babies baby food that she doesn't realize how funny baby laughs are when their mouths are full of cereal and squash.
... but mostly because daddies are the best at making babies laugh, hands down, and helping mommies to slow down and enjoy the fun moments.