Blue: calm, relaxing, the ocean.
Blue is a “cool” color; generally cool to the touch. We go to the beach, and we enjoy the blue skies, and the blue water. My theory is that we love the color blue as human beings, because we need water to survive.
The interesting thing about studying the color blue is that the shade of blue comes in an infinite variety. All the blue photos of mine which I’ve found come in all intensities of blue; the next series of photos I’ll do is “aqua-marine/turquoise” color— which actually looks different from blue.

Note that the color and shade/tone of blue changes depending on the color next to it. I’ve discovered the most intense contrast with blue is the color orange.
Here are some of my favorite blue photos:
Other inspiration: