Most artists, being obsessed with being original, police their little kingdoms of creation to keep it clean of any overt signs of influence. So many conversations about tracing the date when X saw this, Y saw that, in order to deduce whether or not they came up with the idea/concept on their own. Whether Raymond Red was aware of Borges or Kafka before he made Ang Magpakailanman (He was not, which, according to Art's traditional grading system, makes his film more original, and therefore more excellent.) whether Z painted like that before he saw A's copy of Juxtapoz etc, etc, etc.
This is not an exceptional state of affairs, of course. The entire idea of art as it is presently conceived, with all its Renaissance-to-Romantic era notions of genius etc, enshrine originality as the foremost criteria of quality. When originality is gold, it is no surprise that so many people obssess over it.
The rise of sampling and appropriative art methodologies have put these old assumptions/metaphysics in question, but probably no one has summed up the alternative viewpoint quite so powerfully as Jonathan Lethem does, in the article found here:
Check it out.