Why the Whys?

WHY
/ʰwaɪ, waɪ/ Pronunciation Key - Show Spelled Pronunciation[hwahy, wahy] Pronunciation Key - Show IPA Pronunciation adverb, conjunction, noun, plural whys, interjection
–adverb 1. for what? for what reason, cause, or purpose?: Why did you behave so badly?
–conjunction 2. for what cause or reason: I don't know why he is leaving.
3. for which; on account of which (usually after reason to introduce a relative clause): the reason why he refused to go.
4. the reason for which: That is why he returned.
–noun 5. a question concerning the cause or reason for which something is done, achieved, etc.: a child's unending hows and whys.
6. the cause or reason: the whys and wherefores of a troublesome situation.
–interjection 7. (used as an expression of surprise, hesitation, etc., or sometimes a mere expletive): Why, it's all gone!

Why do people like to ask why?

Do we need to know why?

Or, do we want to know why?

If you need to know why, then fine.

But if you don't need to, then why 'why'?