Michael Haneke said this quote

I like the multiplicity of books, because each book is different in the mind of each reader. It's the same with this film - if 300 people are in a cinema watching it, they will all see a different film, so in a way there are thousands of different versions of Caché (Hidden). The point being that, despite what TV shows us, and what the news stories tell us, there is never just one truth, there is only personal truth.