Oxytocin: A neurotransmitter known as "the bonding hormone."
Pheraamones: Olfactory signals that are exchanged between people.
Seratonin: A neurotransmitter that contributes to well-being and happiness.
Dopamine: Motor control, motivation, reward neurotransmitter.
While I was watching a quasi-documentary, I saw a computer pose the following question to a programmer: "What is the highest value?" Dude typed in "infinity," first. Then "love," and then "life." About then I had to pee, and on the way to the bathroom I came up with the answer: The highest value is the next highest value plus one. In my world then value is relative.