Harvard has a famous theory: The difference between people lies in their spare time, and a person's fate is determined between 8 pm and 10 pm. Set aside 2 hours every night to read, study, think, or participate in meaningful speeches and discussions. You will find that your life is changing. After a few years of persistence, success will beckon to you. Einstein said that the difference between people mainly depends on the use of time beyond eight hours. It's true what you say.