My business is too difficult. My business is trying to arouse human pity. There are few things that'll move people to pity, a few, but the trouble is when they've been used several times, they no longer work. So it happens, for instance, that a man who sees another man on the street corner with only a stump for an arm will be so shocked the first time that he'll give him sixpence. But the second time it'll only be a threepenny bit. And if he sees him a third time, he'll hand him over cold-bloodedly to the police.
Peachum in Act 1, scene 1, pp. 5-6 - The Threepenny Opera (1928)