Lesson 1: Why React Hooks?

Before Hooks, stateful logic lived in class components — verbose, hard to reuse, and confusing with this. Hooks let you use state and other React features in plain functions.

function Counter() {
  const [count, setCount] = React.useState(0);
  return <button onClick={() => setCount(count + 1)}>{count}</button>;
}

Two rules: only call Hooks at the top level, and only from React functions.