What's so bad about being selfish?

Imagine an entirely selfish morality. Do not think of selfish as a child not sharing toys or a shoplifter. Instead think of it as looking out for oneself above all else, but with the sense to look down the road. A reasonable system of rules can be created from this.

Start with this question: Would I want this to happen to me? Think of it as a variation of Jesus' command to do unto others as we would have them do unto us.

I would not want to be murdered, so I do not murder. If we all do this, then no one gets murdered and we all benefit. Collectively we can set up laws and punishments to discourage murder. Do the same for stealing. From selfish motivations we can acheive a greater good.

Here's the catch: This system is based partially on the fear that we will be subject to the same things we do to others. Imagine everything as a competition. If you will never lose then winner takes all is a pretty nice system for you. But none human is unbeatable, everyone loses eventually, and that's when we see the need for rules which protect against total loss. A murderous world might be good for someone that always wins, but everyone loses eventually, so we want to set standards so that defeat is not death.

With rational, selfish people, a safer, more prosperous world could be created. As individuals become too dangerous the masses would recognize the threat and deal with it. There would be balance, no one would be allowed to become significantly more powerful than another since this would threaten each individual.

There are two major threats to this system. One is the formation of sub-sets of the population which choose to act more closely with each other, against the greater population. Normally these could be recognized and dealt with, but if the threat was not noticed in time, it could lead to excessively powerful groups and the individuals within, destroying the balance. At this point the will of a few could be imposed on everyone.

The other threat is God. According to Christian thought he is all-powerful. This means that he does not need to fear being on the losing end, he will never lose. He can make any rule he wants, do anything he wants, and there is no balance at all. If he was entirely benevolent there isn't too much to fear, but the slightest ill will would be devastating for the target. The Old Testament is filled with stories of what happens when an all-powerful ruler of everything is unhappy.