Why is Debian the way it is?

Debian is a large, complex operating system, and a huge open source project. It's thirty years old now. To many people, some of its aspects are weird. Most such things have a good reason, but it can be hard to find out what it is. This is an attempt to answer some such questions, without being a detailed history of the project.

The fact that Debian is a relatively slow-acting, complex democracy is probably why it has survived for so long, and why it's become the bedrock for so many derivative distributions.