A little boy asked to draw a picture of Heaven might draw pictures of clouds, sunshine, and his dog that was recently ran over by a Suburban speeding down the street. This image might make him feel a little better about the loss of his pet and soften the emotional fallout. Later in life, when he's a man, when he has another dog that eventually dies of age-related illness he will be brought back to those memories of the loss of his first dog. And those images of Heaven he drew will feel empty and he will inextricably feel sick with himself. This new loss leaves him with more emotional baggage than he expected, and he looks back at this childhood exercise with scorn.