AN AGE OLD QUESTION

Why is it that babies find it enormously fun to COVER themselves in food? I can understand if they are feeding themselves, as they don't have the coordination. But why is it that when I feed Lyla myself, she feels the need to smack it right out of my hand and onto everything in its path? I don't believe the answer has ever been found. Its a good thing too, because babies look so darn cute all covered in food...