Nagging is the repetition of unpalatable truths.

"Today, literate people of the space age, in well-populated countries, are not prepared to accept taboos without question."

I learned that economics was not an exact science and that the most erudite men would analyze the economic ills of the world and derive a totally different conclusion.

[G]overnments still pin their faith to some new economic nostrum which is produced periodically by some bright young man. Only time proves that his alleged magic touch is illusory.

Prize-fighting is still accepted as a display worthy of a civilized people despite the fact that all those connected with it are fully aware it caters to the latent sadistic instincts.