Making decisions is the most fundamental “thought” activity we engage in every day. The consequences of our choices, at work and in our daily lives, can range from trivial and fleeting to momentous and far-reaching. Increasingly in our fast-moving world, we need to make decisions quickly, even intuitively. The “Tough Choices” exercise is designed to guide readers through the decision-making process by applying a concept called “the power of one.” Five different vignettes, from work to social, present scenarios where readers are asked to decide who, or what, is most important from among a range of choices, then make, rank—and justify—their decisions.