I once read a quote from a French philosopher that I've never been able to find again, which says that humans are amazingly good at focusing only on what they don't have no matter how much they have. So everybody does it. It's not a bad idea now and then to be reminded that lots of people are goatless, but you can't spend all day marvelling at your own fortune - it takes up too much processing power. It's Rwanda, BTW;).