red stairs

While walking to the library today a woman said hello to me on the street, just, "hello! hi!" I smiled, said hello and she went back to looking at her ipod. Later, after a meeting and lunch, as I was walking, on a completely different street to the grocery store, a man did the same thing, "hello", he said, I smiled, said hello back, and he kept walking...

...is there something going on that I don't know about?