The artist reflected within their work

Do you believe that an artist's work is a reflection of them? I was at the Metropolitan museum on Friday (and walked over 150 blocks in NYC) and it is so amazing seeing all of the art styles and art pieces. And each artists does have their own style, but can we see part of them in their work? I think that we can tell part of their life, like Pablo Picasso's periods. Their creativity, their imagination. What you think is who you are, so art is the tangible reflection of your thoughts. And this definitely includes writing! Because writing is a reflection of someones thoughts, creativity, and beliefs. And it can be so personal like a dairy. So who do you think is the greatest artist who ever existed? And their work?