I was 20, had just bought a 4x5 field camera, and me & a hundred other guys were let go from the local sawmill. I went on UIC (unemployment insurance) and spent the next couple months diving into the deep end of the Zone System of exposure and development for B&W film. I spent hours pouring over the books and days out photographing in the woods.
One day, hiking through the mature temperate rain forest we have here, I suddenly became aware of...everything...all light, all movement, all colours, all of the minuscule details making up the entirety of the forest. It was a gift, lasted about half an hour, and has never happened again.
A somewhat similar thing happened to me the first time I went to art school in Vancouver. It was my first time living in a city, and I didn't adjust very well at first. There was an Emily Carr exhibit at the Vancouver Art Gallery, so I went and really connected with her work done along BC's coast.
When I came to her painting, The Red Cedar, I stopped and fell into the painting. The crowds faded away until it was just the painting and me. I think it lasted about 10 minutes, but there's no way I can be sure.