Why We Write...
I will start with one of my favorite quotes about writing, by Joanne Harris (It happens to be my profile icon/avi):
"You write because you need to write,
or because you hope someone will listen
or because writing will mend something broken inside of you
or bring something back to life."
I use to HATE to write, oh so long ago. Until the 9th grade, it was my least favorite thing to do in school (and being a nerd, that was saying something).
I will not go into the tale as to my evolution from hate to love to need to...
Instead, I will walk through the question based on expanding on the quote above:
"Because you need to write..."
Just like you need to eat, breathe, and move; writing fulfills a similar stimulation to the mind. If you write, you will grow. If you write, you will become a better communicator in both the written and spoken forms. Writing can take you anywhere you want to go. Can let you understand people. Can reveal a deeper self tucked away deep inside. It becomes almost addictive as to what you learn about yourself once you begin to write.
"Because you hope someone will listen..."
Everyone, in some way, would like to be heard or understood a bit better than they are currently. At times, writing, even if you are currently the only audience member, can 'hear' something in the writing. You might be shocked by just how different an idea or a thought that is 'in your head' already, changes once you write or speak it aloud. That said, as soon as you start sharing what you write, you touch those that read it. Touch them in light or profound ways.
"Because writing will mend something broken inside of you..."
There is perhaps no greater salve to one's psyche than to write out your mental and emotional pains and anguishes.
Suffer depression? Write
Suffer abuse? Write
Suffer period? Write
Suffer self-loathing? Write about it! Write the contrast and force yourself to be honest about it.
"Bring something back to life."
This is similar to the previous. Writing can bring back the past with as much clarity as a photograph can. It can make a memory more vivid.
Just as easily, sometimes it is easier to write a letter to someone that is out of your life (physically or metaphysically). It brings comfort, or it helps to free the tears that are currently drowning your soul. There is a melancholic beauty to this process.
Hope this gives you enough reasons to write. Once you begin, I hope you find what you are looking for and find a lot of treasures you were never expecting. When you do, you'll understand...