Use it when something is so surprising that usual questions aren't strong enough.

Expressing Astonishment

Fits informal settings like chatting with friends, not formal reports or meetings.

Casual Conversations

Highlights that you're really puzzled about how someone did something.

Suitable when questioning the rationale behind someone's choice or behavior.

Shows that you find someone's actions or reasoning hard to believe or understand.

Indicates worry or care about someone's well-being or choices.