I sat at my desk, feeling the stillness and silence of the house around me.  Defeated, I pressed my palms against my forehead and sighed.  Write something, she said.  Anything, and I'll read it.  At the time, I thought it was a good idea, that it would force me to be creative and use the talent I had.  Now, hours later, surrounded by crumpled pieces of paper and plagued by the half-formed ideas in my mind, all I could think was, what talent?  I couldn't do this, I wasn't creative.  Sure, I had a small talent for writing but all I really felt I could do was essays, school stuff.  I was no good at making up stories, and even if I was, no one would want to hear them anyway.  Similar thoughts of doubt swirled through my mind, forcing me to put down my pen and contemplate the inevitability of my failure. 
You've got no ideas, no material. True.  In creative writing the most important rule is to write what you know.  Write about your feelings, your life, your dreams, because that's what you know best, what's easiest to describe.  But my feelings and dreams were too personal, too private, or too embarrassing to say out loud.  And my life, well... I could count on one hand the number of risks I had taken during my sixteen years, and none of those resulted in anything worthy of being put down on paper.  Not only did the phrase, “write what you know” leave me completely devoid of subject matter, it also left me to contemplate the numerous years of life I'd lived and the comparably little I had to show for them.  My life was hopelessly boring and anticlimactic, and, as a result, my writing was nonexistent. 
Even if you did come up with something, it wouldn't be original.  Also true.  Whenever I did manage to formulate an idea that I deemed halfway decent, it was immediately dismissed for being too similar to this, too reminiscent of that.  I felt that every story, every plot, every character in existence was something of a cliché.  To a certain extent, everything's been done before, so why should I, with my meager talent, attempt something that's been done thousands of times by people far more capable than I will ever be?  I felt, through some paradox marred by self-doubt and insecurity, that I was above rewriting ages-old clichés and yet completely unworthy of doing so due to mu utter lack of greatness compared to those who came before me.  In short, I felt that I could never come up with any independent, original work of which I could truly be proud, so there was no point in trying.
What's the use?  It's not like writing a simple little story is going to change anything.  It's not going to make me a better writer, and it's not going to give me any ideas for writing in the future.  And it's certainly not going to give my seemingly dormant, unproductive life any direction or meaning.  Is it?  I guess it comes down to this: I as a person am just as conflicted and confused and lost as my writing.  I have no idea what form my prose or my life will take.  But I don't just stay locked away, editing and improving and perfecting myself until I produce a version of me that is suitable to show to the world, do I?  Of course not.  I do what I have to do to learn who I am, how I want to live my life, and what I want to do.  I make mistakes and I fail, but I pick myself back up again, and all I really have to do is try.