Studies show that our left side is our “best” side:

Participants were asked to rate the pleasantness of both sides of male and female faces on gray-scale photographs. The researchers presented both original photographs and mirror-reversed images, so that an original right-cheek image appeared to be a left-cheek image and vice versa.

They found a strong preference for left-sided portraits, regardless of whether the pictures were originally taken of the left side, or mirror-reversed. The left side of the face was rated as more aesthetically pleasing for both male and female posers.

These aesthetic preferences were also confirmed by measurements of pupil size, a reliable unconscious measurement of interest. Indeed, pupils dilate in response to more interesting stimuli – here more pleasant-looking faces, and constrict when looking at unpleasant images. In the experiment, pupil size increased with pleasantness ratings.

Researchers think it could be that the right side of the brain controls the left side of the body. The right side also is said to be what controls emotions and creativity.

via The Atlantic