Tantra made a T-Shirt with this line and a mug of beer. A common myth, at least among the people I know is that you should slant your glass and pour the beer in very slowly to prevent it from frothing. The website of Budweiser says that you should pour it and allow an inch of froth. The froth is supposed to prevent your beer from oxidization.
So why would you want to avoid the beer from frothing. Maybe you have split the cost of beer and want as much as you can so you cut the froth and pour in an extra inch of beer.