It's nothing but a matter of seeing, thinking, and interest. That's what makes a good photograph. And then rejecting anything that would be bad for the picture. The wrong light, the wrong background, time and so on. Just don't do it, not matter how beautiful the subject is.
The avalanche of time sweeps everything before it. Every individual instant hurtles into oblivion, drowning out the obliteration of the instant immediately preceding it, and then it too disappears under the onslaught of the next and the next and the next. When the avalanche has shuddered past for a long enough time, the perception of the past evolves. Distant events grow beyond mere history and take on the weight of legend.