celltvculture:

According to marketing professors at the University of Arizona, watching repeats is not due to boredom or nostalgia. It’s way more complex. We watch reruns and shell out money for boxed sets because we know what we have seen, and how we will respond to it. Watching “I Love Lucy” 37 times is not the same experience, but 37 different experiences we measure ourselves against. We know what will happen, but how we respond to it emotionally and mentally changes each time. 

Scientific Reason Why We Watch Reruns