Why?

Of all the question words, I like "why" the best. Why?

Who asks about people.
What asks about facts.
How asks about methods.
Where asks about locations.
When asks about times.
Why asks about purpose.

Knowing why leads to the others. Tell me why your company exists and it is easy to figure out what you sell to whom. It doesn't work the other way around.

Who, what, where, when, and how all have objective answers (whether you know them or not). Why is subjective, pointing to underlying motives.

Why has power. Without a reason, without a purpose, the who is aimless, the what is meaningless, the how is mechanical, the where and when are arbitrary.

Why is multi-dimensional. As any 4-year-old knows, there is no limit to the number of times you can ask why. There is always a reason behind the reason.

Why makes us human. The search for purpose separates us from animals who care only about the what, the who, the where, the when, and the how (relating to food and sex, primarily...not that we don't care about those, too...we just add the why).

That's why I like why.