When we ask for reasons in speaking, we can use the phrase why is that? In informal conversations we often say why’s that?:.
an introductory expression of surprise, disagreement, indignation, etc: why, don't be silly! Etymology: Old English hwī; related to Old Norse hvī, Gothic hveileiks what kind of, Latin quī
Why is an interrogative adverb that can be used alone and shows emotions like surprise or anger. For example: I went to Siberia.
