Artists who wait for inspiration to strike spend a lot of time waiting. I know this because I was formerly such an artist. I believed that I should not force my writing, but that I should let it come to me naturally. I thought that discipline was a bad thing; something that went against the grain of creativity. I believe that many people share this same misconception.
But any negative feelings I had towards discipline have been wiped clean from my mind because discipline was the very thing that enabled me to write and complete my novel. I decided to stop waiting for inspiration to strike, and to sit down every single day and write a minimum of 400 words of my book. I made my quota of words no matter how I felt or what was happening in my life. Eventually I got in such a routine of writing each day that sitting down to write did not require a great deal of discipline, and it became something I wanted to do.
I think that any great accomplishment is reliant on practicing discipline. Through discipline, ballerinas can stand on their toes; Olympian swimmers can win races; and writers can write novels.