Lazily evaluating 2+2 requires storing two numbers and an operator for a while, eagerly evaluating requires storing just one number (4, the result). This can b

Lazily evaluating 2+2 requires storing two numbers and an operator for a while, eagerly evaluating requires storing just one number (4, the result). This can be a real problem, for example if you read potentially large network input eagerly and use it to compute a small result lazily. IMO it's always a mistake and IMNSHO the proper solution is always something more nuanced than just "make it eager" or "make it properly lazy".