Paradoxically, it's uncertainty that makes us feel most alive. Think of events that shake you out of your everyday routine: maybe attending a family wedding, making a big presentation, or going somewhere you've never been. It's on those occasions that time seems to slow down a little, and you feel more fully engaged. The same holds true if the experience is risky, like mountain climbing or parasailing. Your senses are sharper. You notice more. Thanks to the release of a feel-good chemical in the brain called dopamine, you get a greater rush of pleasure from chance encounters with people than planned meetings. Good news, financial rewards, and gifts are more enjoyable if they are surprises. It's why the most popular television shows and movies are the ones with unexpected plot twists and astonishing endings.