Beer doesn't ask if it was good. Beer matures as it gets older. You can have a different beer every week without people thinking you are a slut. If you throw out a beer it doesn't come back whining. You know exactly who else has drunk a beer.
Beer tastes better.
A beer won't sit in front of the TV and watch football all weekend. A beer doesn't get jealous when you grab another beer. When you go to a bar you can always pick up a beer. You can share a beer with your friends. You can shoot a beer.