Charles Mackay on speculative folly

Every age has its peculiar folly; some scheme, project, or fantasy into which it plunges, spurred on by the love of gain, the necessity of excitement, or the mere force of imitation.

~ Charles Mackay, Extraordinary Popular Delusions and the Madness of Crowds (1841)

(Cited by Randall Forsyth, "WallStreetBets Might Be New, but Bubbles And Busts Are Not," Barron's, January 30, 2021.)