So I’m thinking along the lines of this (volume warning)
But my two year old just did the same thing while “helping” to feed the dogs. She spilled a few pieces, looked at the mess, and then dumped out the rest of the cup. She exclaimed, “I make a mess” then picked up the pieces, put them back in the cup, and successfully poured it into the dog’s bowl. What breaks in their brain where the task doesn’t go according to plan so they make an even bigger mess?
It’s technically called intrusive thoughts. Kids are notoriously bad at impulse control, so this theory has credence.