One night at Cheers, Cliff Clavin explained the “Buffalo Theory” to
his buddy Norm:

“Well ya see, Norm, it’s like this. A herd of buffalo can only move
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 killing 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, as we 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.”