What is memorable?

As micro-attention and media bombardment grows, I find myself thinking more and more about not what catches my eye, rather what stays in my brain.  I watched a film that I had seen 17 years ago last night and was a bit startled at the level of detail I recalled from it. In this particular case, also interesting was that I first actually visited Japan only (earlier) this year, yet have had nearly a life-long curiousity about Japan's people and perspectives.

Why is it that some images, songs, etc...'stick' and others don't?  What connection(s) enable exact remembrances?

Although I certainly don't have the answers, it is interesting to think about the questions, and to dream.