Not really a joke but funny.
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."