Because I've never been able to say it this clearly, and though it might not be true for everyone, it's definitely true for me:
"A writer writes not because he is educated but because he is driven by the need to communicate. Behind the need to communicate is the need to share. Behind the need to share is the need to be understood. The writer wants to be understood much more than he wants to be respected or praised or even loved."
— Leo Rosten - American Novelist