"How your partner smells is as important as their appearance, according scientists at the University of St. Andrews. They studied the effects of phermones and facial appearance on long-term relationshuips"
"Revenge is Sweet" psychology article
"Do animals take revenge?"
"According to Stephen Beckerman, an anthropologist at Penn State University USA, vengeful behaviour is widespread in the animal kingdom. Blue-footed boobies (a type of bird), elephant seals, side-stripped jackals and European moorhens are all known as 'punishers' - they response to injuries by attacking those animals who hurt them. When it comes to primate, revenge gets more subtle - the injured individual may go for the relatives or allies of the guilty partry, instead. But the point is the same; the behaviour acts as a negative reinforcement, forcing the attacker not to damage the victim any further"
Link from Satanism page on violence (probably) http://www.dpjs.co.uk/violence.html ("Human beings are animals, sometimes better sometimes worse...")