And you have to accept that and shift your expectation to accommodate what you observe

I agree with you that photography is about perception of the world, even if we talk about photographers who stage work. But let’s focus on what we could call descriptive or documentary practice. The most interesting photographers in that field are those who manage to find a proper balance between perception and the idea. I was talking about this with Paul Graham a few weeks ago, who said that you can set out with the best possible idea, open your door, go outside, and the world changes that idea. And you have to accept that and shift your expectation to accommodate what you observe and evolve with it. What you produce in the end will probably be quite different from the initial idea. This is what photography is about.

via.