Here’s a story that has stuck with me for over 30 years. When I was still in college, my best friend, who was majoring in Finance, once asked me what Annual Percentage Yield (APY) I was getting on my savings account with the local bank. “About four percent,” I confidently told him. There was just one problem. I had absolutely no idea what APY I was earning. At some point, someone had told me it was around 4%, and I assumed it stayed there forever. Because that's how banks wor