Every night, Frank would go down to the liquor store, get a six pack, bring it home, and drink it while he watched TV. One night, as he finished his last beer, the doorbell rang. He stumbled to the door and found a six-foot cockroach standing there. The bug grabbed him by the collar and threw him across the room, then left.
The next night, after he finished his 4th beer, the doorbell rang. He walked slowly to the door and found the same six-foot cockroach standing there. The big bug punched him in the stomach, then left.
The next night, after he finished his 1st beer, the doorbell rang again. The same six-foot cockroach was standing there. This time he was kneed in the groin and hit behind the ear as he doubled over in pain. Then the big bug left.
The fourth night Frank didn't drink at all. The doorbell rang. The cockroach was standing there. The bug beat the snot out of Frank and left him in a heap on the living room floor.
The following day, Frank went to see his doctor. He explained events of the preceding four nights. "What can I do?" he pleaded. "Not much" the doctor replied. "There's just a nasty bug going around."
A herd of buffalo can move only as fast as the slowest buffalo, and when the herd is hunted, it is the slowest and weakest ones at the back that are killed first. This natural selection is good for the herd as a whole, because the general speed and health of the whole group keeps improving by the regular culling of the weakest members.
In much the same way the human brain can only operate as fast as the slowest brain cells. Excessive intake of alcohol, we all know, kills off brain cells, but naturally it attacks the slowest and weakest brain cells first.
In this way, regular consumption of beer eliminates the weaker brain cells, constantly making the brain a faster and more efficient machine.