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 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, making the brain a faster and more efficient machine. That's why you
always feel smarter after a few beers.