I never stop being amazed by the sheer _volume_ of human creativity that is available on the internet.
From billions of hours of podcasts and videos to enough beautiful art to fill a thousand museums to more music than anyone could ever listen to to the sheer breadth and depth of literature, both original and fanfics, as well as essays up the wazoo on all sorts of topics and even peer-reviewed or non-peer-reviewed research about almost every imaginable subject.
It's breathtaking.