Why is it so hard to write?

I have so many talented friends who have an amazing voice and sense of humor that I know would benefit the world, but like me they can never think of something to write. Perhaps, their lives are so inundated with ideas that they can't sit down in front of their laptop and decide on what to write first. I wish it were some how easier for them and the rest of us to tell our stories, perhaps the world would be a better place if we could only get more of what's inside us out.