Reasons only bring more questions

Like I said, even an answer about what happened to Leif, from him, only brings more questions. If he died from loneliness, lack of purpose, debts and pain, WHY couldn't he find a purpose in life? Why couldn't he find a life partner who didn't bring him pain? Why couldn't he control his spending? Why did he have such a need for speed and weapons. The questions will go on all my life.