Developers should know How, What and Why

The most important word I learned all over these years is "why". People get worried about asking "Why?" for several reasons (like showing you might not know something you should) but I found out it's a question clients love to be asked, it makes them feel like you really want to be inside whatever they want you to do.

This is so true. I've been using this model to specify requirements in large organizations, organizing the requirements in HOW, WHY, WHAT-sections roughly equivalent to business goals (WHY), features / requirements (WHAT) and a system specification or in best case running source code (HOW).

I think they missed a few.

I KEEP six honest serving-men (They taught me all I knew); Their names are What and Why and When And How and Where and Who.

http://www.kipling.org.uk/poems_serving.htm

What's probably even more important than only being able to design the How after you know the Why and What is that Why is a very very very good motivator.

In general I noticed that people much prefer their work when they know why they're doing it. If you disclose enough information, they might even surprise you and work more than you ask of them because they feel the Why is that important.