Next.js · Server Components · Junior · Debugging
Why can't you use useState or onClick in a Server Component?
Short Interview Answer
Those require client runtime and interactivity; Server Components have no client hook runtime.
Detailed Explanation
Mark interactive leaves with `'use client'`. Keep parents as Server Components when possible so only interactive islands hydrate. Passing event handlers as props from server to client is not allowed — pass data and define handlers in client code.
Common Mistake
Sprinkling 'use client' at the root and losing RSC benefits.