“The people who create and refine tech, games, and interactive experiences are very good at what they do,” says Alter. “They run thousands of tests with millions of users to learn which tweaks work and which ones don’t—which background colours, fonts, and audio tones maximize engagement and minimize frustration. As an experience evolves, it becomes an irresistible, weaponized version of the experience it once was. In 2004, Facebook was fun; today, it’s addictive.”