Every good book should be entertaining. A good book will be more; it must not be less. Entertainment…is like a qualifying examination. If a fiction can’t provide that, we may be excused from inquiring into its higher qualities. - C.S. Lewis
No doubt Jack the Ripper excused himself on the grounds that it was human nature.
[To a first-term congressman who wanted wanted excused from voting with the party to satisfy his biggest contributors:] Son, if you can't take their money, drink their whiskey, screw their women, and then vote against 'em, you don't deserve to be here.
My doctor says that I have a malformed public-duty gland and a natural deficiency in moral fibre, and that I am therefor excused from saving Universes. - Douglas Adams
Domestic violence is frequently excused when alcohol and other substances are involved. - Asa Don Brown