Do you know when children start to feel guilt? Scientists at the University of Iowa do, because of this little experiment. They gave children a toy, told them that the toy was very special to them, and asked the child to be extremely careful with it. Then the toy broke.
The toy, usually a doll or a model boat, was rigged to fall to pieces as soon as the child started playing with it. When the break happened, the researcher would say, in a mild tone of voice, "Oh my." Then the researcher would "observe" the child for the next 60 seconds. Kids think a two minute time-out is long, and that's when they aren't being stared at by a stranger whose cherished toy they've just smashed.
The kids were sometimes as young as two (which is the age when people start to feel guilt). They sometimes tried to fix the toy, but usually hugged themselves, tried not to meet the researcher's eyes, or covered their face with their hands. The single worst minute of their young lives later, the researcher took the pieces of the toy out of the room, came back with a replica, and told the child that the break wasn't their fault and the toy had been fixed. And everyone lived happily ever after and certainly didn't wet the bed that night.
The study was meant to demonstrate something other than "kids go fetal when they're faced with the potential wrath or grief of a stranger." Children who had more extreme responses to the broken toy seemed to be better-adjusted and have fewer behavioral problems later in life. So now you know that self-imposed suffering is the key to later happiness. And you know not to trust scientists.