Does art immitate life, or is it the other way around?

Do you ever have those moments where you think, "which came first the chicken or the egg?" I did this week when in the middle of a crowded sidewalk, I nearly lost it laughing over what I saw happening around me. I was walking down a busy street in Salt Lake City surrounded by people all wearing shirts and ties or nice dresses or skirts. I was by an enormous office building that provided the hoards of professionally dressed individuals, but it still caught me off guard. About half a block down I noticed a bus stop. Normally that would not be a huge eye catching fact, but what I saw immediately caught my attention. There were two bus benches next to the sign that were full with people waiting. Then directly behind the sign was a man that was clearly the first person in line. Behind him were half a dozen men and women, dressed to the nines waiting in a perfectly straight line, arms placed at their sides and looking straight forward. That was a peculiar sight for me as I am used to passing bus stops where most everyone is waiting around in a group, talking, listening to music, sitting on some grass, etc. That alone was unique when all of the sudden the three people walking next to me on the sidewalk made a sudden turn left from their forward movement, and continued the succinct line until in neared the bushes and made a sharp 90 degree angle. Once again, there was no observable facial expressions, no friendly pleasantries, just order. It all looked so familiar when it hit me where I had seen this scene before. Harry Potter! If you recall in what I think was the 5th Harry Potter movie, as they are trying to disguise themselves to break into the Ministry of Magic, all of the workers lined up single file in their professional apparel taking turns one by one to enter. This is why this looked so familiar. And I started to laugh. Because how often are you walking down a street to look up and see anything that makes one conclude that Hogwarts may not be that far off from reality. So the question at hand, which did come first? Does art imitate life, or does life imitate art? I honestly have no idea. Was this experience just a quirky coincidence, did authors/directors see this at some point and conclude this is what the scene would look like, or do we unconsciously evolve into what we see, hear, or experience around us? And if the third is the case, how much exposure would place us in danger of becoming what we see? Just some food for thought as we move along with the world around us.