I am sure that 'blocks' exist in all forms of creativity. When I speak of 'block' I mean inhibition. IMO, at it's most basic, inhibition comes from fear and/or shame. All kinds of other more complex sentiment (envy, perfectionism) are based or built on these. When a person with creative impulses defeats themselves again and again when they attempt to follow those impulses it's some messed up mental mechanisms trying to protect them.
In pretty much every creative endeavor that requires self-expression or intelligence - music, writing, computer stuff, I suffer from inhibition. I can do so much, and then bammo - the road ends. I have made great advances in my ability to write in the last five years, but I still struggle a lot. I feel good about my sewing, and I am able to keep at that. I guess what makes it safe for me is that is is free from obvious self expression (differing from writing or music) and from the possibility of impressing people with one's intelligence.