You start to learn how to invest that money, which is a job in itself. You can't just put it in T-bills or bonds and call it a day. It's not impossible to book

You start to learn how to invest that money, which is a job in itself. You can't just put it in T-bills or bonds and call it a day. It's not impossible to book 10 to 15% (or higher) returns by actively managing your money. But it's not exactly easy.