Because...

... some people don't see me all the time.
... some people wish I were quieter.
... I want to practice my writing skills.
... there are things that are too complicated for mere sentences, and why should we limit ourselves?
... my world is bigger than me.
... the bright side of things are better seen from a different point of view.
... the things in my life are stupendous enough to be recorded somewhere.
... why not?