In the 60s, Walter Mischel conducted the well known marshmallow experiment to study the effects of delayed gratification. He gathered a bunch of 4 year olds and gave them a marshmallow while promising to give another if they waited 20 minutes before eating the first. He then tracked their progress till adolescence and discovered that those who were able to wait were better adjusted, more dependable and scored higher in tests. The results seem to support the conventional wisdom that willpower and good impulse control are important to succeed in life.
Good things do in fact come to those who wait. Maybe if I wait long enough, I can get an iPad?