Before the 2008 financial crisis, a neighbor of mine took out a home-equity loan from Wachovia, paying about 5%. The Wachovia never sent the appraiser home, but that’s not the weirdest part of the story. My neighbor asked his financial advisor what to do with the money left over after paying some expenses. The advisor suggested a money manager who guaranteed a 12% return, explaining that “you’re borrowing at 5% and paying 12%—you’d be a fool not to do that.”