The other day my friend's infant came running into the living room yelling "I did it mommy, I did it". She just relieved herself in the potty, and she was psyched. Pscyhologists like Frued and Erikson have spoken about the importance of the so called "anal" stage. You may be tempted to dismiss this as out-of-date psychological babble, but if you really think about it using the bathroom is one of the first achievements of a child. They begin to see that pooping appropriately makes mommy and daddy happy. Conversely, they begin to see that pooping inappropriately can anger mommy and daddy, and can perhaps be used as retaliation for not getting what they want. In a lecture given by Dr. Edward Sheridan, he playfully refers to this as "letting the shit fly". Again, you could dismiss this, but if you really think about it, the way parents react to a child's potty success really is one of the first experiences a child has of being approved and disapproved of. It's also one of the first experiences of control, albeit small and early, the child exhibits. Finally, if pooping is this big of a deal, just think about how important major events later in adolescence become.