Since the Financial Crisis of 2008 and 2009, insurance agents, stock brokers, and bank representatives have been in high gear selling life insurance products to investors clamoring for anything that ensures them against the drubbing they received in the markets. They hear of enticing promises like "Guaranteed Income," "Guaranteed Principal," and "All the market's upside with none of its downside" and they find them hard if not impossible to resist. Are annuities and indexed life products as good as their promoters claim they are?

One of the most powerful forces in the universe is that of inertia. It is defined as a property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an...