It depends how far into the future you are predicting. If you can predict one day, you might want to try your luck with the ponies. However, if you could predict a week ahead but not beyond, you may not want to do anything, because any changes you make a week from now, could have unimaginable impacts on the future. You might not meet the person who was destined to be your wife. Thus you would not have children. The child that was to grow up and find the cure for cancer, be the leader that ends war or be the person who keeps a blind person from walking into the path of a car would not exist and everything would change. The move, "Its A Wonderful Life," gives an idea of how one event can have unbelievable impactss on so many people.