“affection, sympathy, empathy, honesty, altruism, mutual understanding, enjoyment of each other’s company, trust, and the ability to be oneself, express one’s feelings, and make mistakes without fear of judgement from the friend.”

Affection: an objective feeling of bonding emerging from heightened levels of oxytocin and conditioned by repeated exposure to each other’s company.

Sympathy: perception of each other’s viewpoint on emotional matters.

Empathy: understanding and sharing of each other emotional state.

Honesty: straightforwardness, integrity and truthfulness during interactions.

Altruism: concern and caring for each other’s welfare.

Mutual understanding: perception of each other’s viewpoint (in general).

Trust: confidence and willingness to rely on each other’s judgement.