Letters 97.10

All ages will produce men like Clodius, but not all ages men like Cato. We degenerate easily, because we lack neither guides nor associates in our wickedness, and the wickedness goes on of itself, even without guides or associates. The road to vice is not only downhill, but steep; and many men are rendered incorrigible by the fact that, while in all other crafts errors bring shame to good craftsmen and cause vexation to those who go astray, the errors of life are a positive source of pleasure.

Seneca, Letters to Lucilius 97.10, translated by Richard Mott Gummere