Some of you might be asking why go to all the trouble of building a world? Why not just write the story and not worry about such details? The answer is simple, well to me it is. Defining the world that your story is set in develops the story on a whole different level. It makes it feel real, gives it more depth, and more possibility.
If you're like me, the world building comes after or during the writing process. In which case, I have a copy of the questions on hand and answer them as I write. Sometimes though, I like to answer the questions before I start writing; giving myself a solid base to build up from, and it is by no means a waste of time.
Knowing if the government system in your world is a democracy and not a monarchy can change the entire story line. Even if it seems like the questions I use are not vital to the story, they are important and can influence a character's decisions, attitude, and dialogue.
Say the leader of the land your story is set in is not well liked. He makes bad decisions, and is not working toward the good of the land. If the government system is a democracy, your characters aren't as likely to raise an army and overthrow the government just to get rid of him. Now your antagonist might, especially if he thinks he can do things better, but not your protagonist, he'd probably rather wait and do things the democratic way and wait till the next election to vote the bad leader out. Especially, if he's not the real problem. But, if your government system is a monarchy then the only way to get rid of the guy is to oust him in a coup or war.
The people and country dynamics also count toward how your characters will act in your story. Your characters may never meet an elf in your story, but if they exist in your world your characters are going to have an opinion about them. Your story may take place in one country only, but if there are other countries in your world then the people from those places will be different from your characters, with different customs and maybe even different languages, and your characters will react to them.
You also might be asking what qualifies me to discuss this. First off, in my own writing I have built over a dozen different worlds with different creatures and environments. Second off, I am a Biologist, with an MS in Biology, emphasizing wildlife, so I know what I'm talking about. You might not believe it, but a good understanding of Biology is a great foundation for world building.