Remorse

"Chronic remorse, as all the moralists are agreed, is a most undesirable sentiment. If you have behaved badly, repent, make what amends you can and address yourself to the task of behaving better next time. On no account brood over your wrong-doing. Rolling in the muck is not the best way of getting clean."
--Aldous Huxley,
"Brave New World"
Foreword, to the 1946 edition