It's the sort of thing Pratchett offers as a sour reflection on the world as it is, rather than the world as it ought to be. The last part, as you note, is: "

It's the sort of thing Pratchett offers as a sour reflection on the world as it is, rather than the world as it ought to be. The last part, as you note, is: "And at the other end of the bar the world is full of the other type of person, who has a broken glass, or a glass that has been carelessly knocked over (usually by one of the people calling for a larger glass) or who had no glass at all, because he was at the back of the crowd and had failed to catch the barman's eye." ...and both quotes are offered in The Truth, which offers more than a few critical comments around the glass-should-be-bigger set.