People whose social perceptions are impaired, such as autistics as one example, are probably the most themselves.
Perhaps that's what makes us more human-like. If we always behaved without regard for others, we wouldn't experience the full spectrum of emotions that we have been designed to feel as social beings. Compassion, guilt, empathy, embarrassment, shame, happiness, anger - these are not fully expressed if we're by ourselves. Of course, there are feelings that occur when we're lonely, but even then, those feelings prompt us towards finding others for their companionship in order to remove the aversive feelings of sadness and loneliness.
Religions probably tap into this humanity as well. The idea that there is a God, or gods, watching over us, instilled from a young age, can keep us from losing our sense of humanness. The mere sight of a camera, mirror, or fake eyes in a room that you're alone in can make you self-conscious and watch yourself.