React developers often encounter unexpected re-renders with memoized components. The issue stems from JavaScript's referential equality—objects are compared by memory address, not value. This means `{} !== {}`, and creating new objects or arrays on every render breaks `React.memo` optimizations, causing performance hits.

Memoization hooks like `useMemo` and `useCallback` solve this by stabilizing references across renders. `useMemo` caches objects and arrays, while `useCallback` memoizes functions. These ensure React's shallow prop comparison sees unchanged references, preventing unnecessary re-renders in child components wrapped with `React.memo`.

The key is understanding when to apply these tools. Memoize objects passed to memoized children, expensive computations, or context values. Avoid over-optimizing primitives or components that re-render anyway. Always include correct dependencies to avoid stale closures, a common pitfall that can introduce subtle bugs.