[throwawaywego]

Human brains are optimized for prediction of future events, because this helps with survival (eg: you can predict a winter coming up, so you stock up on food).

Randomness is by (some) definition unpredictable. But humans are so eager for pattern recognition that they will see, or expect, patterns that just are not there.

"Pareidolia is the tendency to interpret a vague stimulus as something known to the observer, such as seeing shapes in clouds, seeing faces in inanimate objects or abstract patterns, or hearing hidden messages in music." and also: https://en.wikipedia.org/wiki/Apophenia#Causes

On a similar note, humans are terrible at coming up with random/unpredictable sequences. If you ask a group of test subjects to pick a random number between 1 and 10, you get a huge edge when you guess 3 or 7.