As a way to allow the breweries to continue operations during Prohibition, beer was limited to max 2.3% alcohol. It's been stuck like that ever since.

Here in Canada, one of the first things we do when we meet an American visitor, is take 'em out for a pint. Then over a proper (at least 5%) pitcher, we explain why American beer is like making love in a canoe. By pint number three, the story usually comes back, as one they just made up.