Like every other American kid I was raised on the notion of competitiveness [is that a word? Now it is...]. It is my team against yours. It doesn't matter how many points we scored or how well we played as long as we scored more than you. It is my candidate against yours. It is my company against yours.
That attitude is one of the most erosive elements of our culture. It always pits us AGAINST someone else. The Mekubalim teach that there is no true "otherness". We are all part of a huge soul that was fragmented into different parts but at it's root remains connected. So when you lose in life - I also lost. I can NEVER benefit from someone elses misfortune because on a soul level his misfortune is mine.
Maybe that is what Hashem is telling us in the tenth commandment. Don't covet what belongs to your friend because if he has it - so do you. If he loses it - so do you.