What motivates you to write?

What is the one thing you need when you sit down to write? I don’t mean the obvious pen and paper or computer, but that one other thing that you always have when you write? Maybe it’s a tall-soy-caramel-macchiato and a corner booth at the local coffee shop. Maybe it’s a stack of papers with all of your research, or an expanding file folder packed full, yet obsessively organized, with research material. Maybe it’s not even a physical thing or place. Maybe it’s nothing more than a seed of an idea or a spark of inspiration.