Do you always make basements in your houses?

I went through a brief basement phase a few years ago but at the time I was just modifying existing builds. It's harder to put a basement in someones else's build than it is to do it when you're building from scratch. I think that's why I kind of got over the urge and I haven't really thought about them very much until I saw this thread. It's something I might try again, in the right circumstances now that I'm doing so many of my own builds.