What intrigues me about a photo is the relationship between the subject and the person behind the lens.
This explains why I find advertisements and models so boring. It's a narrow range of relationships playing out over and over. The subject does their best to look pretty, serious, excited, etc. The photographer attempts to capture a predetermined emotion in order to move product. Certainly, this is an interesting relationship but, due to its abundance, I find it the least compelling.
I like candid shots in which a photographer captures a subject's spontaneous relationship to something else. Although now we are too wise to the beauty of these images and must plan them as well.
If a photo is a snapshot of the relationship between photographer and subject then what is a "selfie"? Surely, not ourselves through our own eyes but through the eyes of some imaginary photographer encouraging us to add another safely constructed image to the archive.