Why is it that I can sit down and try to write a song for hours (or even days) and come up with nothing good, but when I wake up in the middle of the night at 2:15 a.m. on Monday morning I reach to the side of my bed, sling my guitar up to me and lay out a killer song. Why does Inspiration taunt me like this, and why does she not come when I beckon?

The real point - Is inspiration real? Do you have to wait on it, or can you force out something good if you sit down and try? Intelligence would lead me to believe work is what you need, but Experience is telling me she comes when she wants.