Bob Dylan sang about how the times they were a-changin' almost 60 years ago now, and since he sang those words punctuated by blasts from his trusty harmonica, times have continued to a-change. Values and certain behaviors can change, becoming more or less acceptable within society at large, and this can have the effect of making new generations look back on a piece of art, for example, and experience it very differently from how those at the time might've experienced it.