This arises from the deep, insatiable, and innate desire to be authentic, juxtaposed against the reality that nothing new exists beneath the sun. This is true whether we speak of art, writing, or virtually anything else. All great thought is merely reflective of archetypical themes which have and always will exist independent of our own vision. Where we seem to struggle is in our ability to speak clearly of our own observations or inspiration for fear that we will tread upon the existent musings of thinkers who came before us. It can be uncomfortable to accept that those before us have also merely reflected on great ideas which were even then universal and present, independent of the thinker.
Great courage is required to throw off the shackles of fear and face our own authentic thoughts with abandon, be they inspired or not. Easier said than done but required for true inner peace. Otherwise, we exist as mere shadows of our own fear and insecurity - avoiding authentic thought for the irrational fear that it is not original.