Here's a counterintuitive fact, there's a type sequels make more money but most of the time people like it much less.

The type of sequels I'm talking about are repeats (like zoolander), not sagas (like starwars, Avengers)

The reason behind this is that there's not much novelty in repeats. Its mostly the same story as the previous movie just with different characters.

But sagas on the other hand add new characters and storylines to make it novel in each part of the series

Animal studies around the brain's reaction to novelty have suggested increased dopamine levels in the context of novelty. So the brain reacts to novelty by releasing dopamine which makes us want to go exploring in search of a reward

Each new stimuli gives you a little rush of motivation to explore, because it makes you anticipate a reward.

Our brains like new things, they pay attention to whats new, so that we can get excited or scared, which is part of our survival instinct. This hooks us to new and novel story lines.

Hence rewatching the same movie isn't as exciting as watching it for the first time.

Not only should have relatibility but also novelty. Taking the same example of star wars, there was relatibility as we saw but there were also new characters and new story lines that excited the user.