Agatha Christie said about her career, "There was a moment when I changed from an amateur to a professional. I assumed the burden of a profession, which is to write even when you don't want to, don't much like what you're writing, and aren't writing particularly well."
One of the things that first attracted me to writing was reaching the flow state, where you know the material so well, where high demand meets high skill, that your words flow effortlessly. Most of my writing sessions, however, are not like that. I get distracted, I have to figure out what come next in the scene and if the scene is leading me toward the climax, and I tend to edit as I write. But eventually, if I keep writing, I move closer to the flow state.
Don't be afraid of the perspiration. It might lead you to the inspiration.