“We made it less random to make it feel more random,” said Steve Jobs, the CEO of Apple. Jobs was talking about the shuffle feature on the iPod. When they launched that feature the algorithm was completely random, but people started saying that they noticed certain patterns when a song was repeated and the general sense was that Apple had designed this all powerful ability to identify their preferences. So what did Jobs do? He made the algorithm less random.
The human mind/brain has this built-in need to find order in chaos. We are constantly looking for patterns or certainty, it is part of our survival instinct. However this also creates our blindspots.
With this in mind we have to rely on external unbiased tools to help us see the wood for the trees.