Of course, like all the informal inhabitants of the University the roaches were a little unusual, but there was something particularly unpleasant about the sound of billions of very small feet hitting the stones in perfect time. Rincewind stepped gingerly over the marching column. The Librarian jumped it. The Luggage, of course, followed them with a noise like someone tapdancing over a bag of crisps.
When the movies first started, audiences were dumbstruck to see actresses walking around in evening gowns. They'd never seen anything like that. They wanted to be like those actors and actresses, so the movies informed their behavior. A lot of people started drinking martinis and smoking cigarettes because they felt it was cool.