You've probably heard the joke about why a ham sandwich is better than eternal happiness:

• Nothing is better than eternal happiness.

• And a ham sandwich is better than nothing.

A ham sandwich isn't perfect, but it's better than having no food at all.

Do you want to live in a perfect society? Find a perfect spouse? Have a perfect job?

You can't. They don't exist, at least not on earth.

If you insist on "perfection or nothing," then you'll probably end up with nothing. Not even a ham sandwich.

The worst problem with "perfect" goals isn't that they're unattainable. It's that they lead us to reject good but imperfect goals we can actually achieve.

Human societies are imperfect because human beings are imperfect. That's not going to change. Attempts to create a perfect society usually cause more of the evils they're trying to eliminate, such as the terror and mass slaughter of the French, Russian, and Chinese revolutions.

No matter how good a society is, there will be things about it that some people dislike. Some of the things will be real problems that should be fixed. Others will either be minor problems or subjective judgments that should be left alone.

The French philosopher Voltaire said it well: "The perfect is the enemy of the good."