I’ve already written about how ineffective the Why? question can be, in a couple of previous posts (one and two).

I’ve found at least a good way of using Why?: it’s the 5 Whys technique used for root cause analysis: asking 5 times the Why? question in the right way, you can go to the root cause of a problem.

Here is an example you can find in this Six Sigma site:

Problem Statement: You are on your way home from work and your car stops in the middle of the road.

1. Why did your car stop?
  – Because it ran out of gas. (first why)
2. Why did it run out of gas?
  – Because I didn’t buy any gas on my way to work.(second why)
3. Why didn’t you buy any gas this morning?
  – Because I didn’t have any money.(third why)
4. Why didn’t you have any money?
  – Because I lost it all last night in a poker game.(fourth why)
5. Why did you lose your money in last night’s poker game?
  – Because I’m not very good at “bluffing” when I don’t have a good hand.(fifth why, root cause)