At 16, Buffett was once obsessed with betting on horse races and lost $175 in a single day. Think about it, that amount was equivalent to 5-10% of his net worth. When he got home, Buffett bought a huge ice cream and calculated how many newspapers he would have to deliver to earn it back. He regretted betting on every race, thinking he could win it back. But the unusual thing is that was the last time he did something like that. Everyone makes mistakes. The problem is that some people remain oblivious, while many quickly become enlightened and never make the same mistake again.