"why" can be compared to an old Latin form qui, an ablative form, meaning how. Today "why" is used as a question word to ask the reason or purpose of something. This use might be explained from a formula such as "How does it come that ...". If you meet an old friend of yours, whom you never expected to meet in town, you can express your surprise by saying: Why, it's Jim! This why in the ...
11 Why is it that everybody wants to help me whenever I need someone's help? Why does everybody want to help me whenever I need someone's help? Can you please explain to me the difference in meaning between these two questions? I don't see it.
Why do we say GBP instead of UKP? - English Language & Usage Stack Exchange