Intelligent discontent is the mainspring of civilization. Progress is born of agitation. It is agitation or stagnation.

Eugene V. Debs (1855-1926) American union leader, activist, socialist, politician

Speech (1908-05-23), “The Issue,” Girard, Kansas
    (Source)

Impromptu speech in the town Debs was living in after his third nomination for President on the Socialist Democratic ticket.