In the past most data orginated in a database because it was deemed important enough by users that they entered it manually (patient charts, student records, inventory, etc.).
Today, the bulk of "big data" is stuff like web click stream analysis, phone call records, highway traffic monitoring, serialized application objects, etc. Most of it (% of total volume) is derivative, duplicated, and mundane. We have to slog through gigabytes and terabytes of digital.. detritus.. to produce little nuggets of relevent business intelligence.
"The universe is complicated and for the most part beyond your control, but your life is only as complicated as you choose it to be."