io9 has a nice column about writers & writing blocks, & they’ve included not just what the block was but how the person got past it.
Self-doubt, self-doubt, self-doubt. Time. Other people’s doubts. Not selling anything. But this one, contributed by Eugene Fischer, was my biggest:
My biggest stumbling block becoming a writer was actually deciding it was an acceptable thing to do with your life.
I never really did decide it was an acceptable thing to do with my life. It was more that it was the only thing I could do for a year after 9/11 and had fallen apart: I spent all of 2002 writing a novel and playing with our kittens.