Gladiator Mosaic, from Villa di Dar Buc Amméra at Zliten, in the Archaeological Museum of Tripoli. Photo from Livius.org.

Severity is the best corrective, but loses its efficacy by over-use.

On Clemency. From Seneca’s Moral Essays. Translated by John W. Basore. The Loeb Classical Library. London: W. Heinemann, 1928-1935. 3 vols.: Volume I.