Let’s talk about something simple but powerful: Fitts’ Law. It comes from research by psychologist Paul Fitts in 1954, and it’s explained beautifully in Universal Principles of Design (pages 98–99). The idea is this: The time it takes to reach a target depends on two things: how far it is and how big it is. That’s it. Closer and bigger = faster and easier. Farther and smaller = slower and harder. It sounds obvious, right? But obvious things are usually the ones people ignore. And in design… ignoring obvious truths is how you lose users. Ouch.