I think it's because you have to use your imagination.

Just like active recall (essentially guess consciously before checking the answeris) a better way to learn I think the less detail their is in the story (book, game, movie, etc) the more you have to do yourself and so it becomes your own experience rather than someone elses.

Yea, that is it.

It is sad that people easily write off memory of nice things as "nostaliga"! Somethings really were nice.