The purpose of being a serious writer is not to express oneself, and it is not to make something beautiful, though one might do those things anyway. Those things are beside the point. The purpose of being a serious writer is to keep people from despair. If you keep that in mind always, the wish to make something beautiful or smart looks slight and vain in comparison. If people read your work and, as a result, choose life, then you are doing your job.
And the purpose of being a non-serious writer too?