The phrase is often used when something is surprisingly good or impressive.

Usually Positive

It's casual and more common in spoken English or informal writing.

Informal Use

It's a metaphorical expression, not meaning actual surprise or amazement.

It conveys a very intense or overwhelming level of admiration or impression.

Often related to experiencing something unexpectedly impactful.

Commonly used to describe events, things or people that are popularly considered outstanding.