Have you heard of The 5 Whys? It's a Six Sigma technique for discovering the root of a problem. Each "why" gets you past surface effects and closer to the cause.

It sounded good in theory, so I tried it on Lydia the other night when she didn't want to put her pajamas on.

Brian: Why don't you want to wear pajamas?
Lydia: Because I don't want to.
B: Why?
L: Because I don't want to.
B: Why?
L: Because I don't want to.
B: Why?
L: Because I don't want to.
B: Why?
L: Because I don't want to.

I'm not impressed with the technique.