As an investment advisor, it’s frustrating to see people mismanage their portfolios. One problem is that ads make it sound so easy to do it yourself. A common refrain is to buy an index fund and don’t sweat other details. But is index investing really so simple? Perhaps the biggest obstacle to a set-it-and-forget-it index fund investing strategy is that investors are human. When bad times hit, they often abandon their strategy; long-ter..