That's not true at all. It's those who made up their minds to be good but aren't who do the most evil.

From Richard Feynman one last letter to his first wife, over a year after her death from TB (incidentally, antibiotics had been discovered and were being tested on humans a few months before her death; a year sooner, and she would have had a good chance of recovery):

My darling wife, I do adore you.
I love my wife. My wife is dead.
Rich.

P.S. Please excuse my not mailing this -- but I don't know your new address.

Perfectly Reasonable Deviations from the Beaten Track: The Letters of Richard P. Feynman.

The whole letter and the rest of the book is well worth reading.

(I found this interesting, given that Feynman was likely the most instrumentally rational physicist ever, and definitely did not believe in any kind of afterlife -- he surely knew he was writing it for himself.)