"If you forgive your enemies, it messes up their heads."

"I learned some invaluable lessons in Nashville that apply to both farming and show business:
Do not corner something you know is meaner than you;
keep skunks of all kinds at a distance;
if you forgive your enemies, it messes up their heads." 

~ Willie Nelson

Willie Nelson, Turk Pipkin (2006). “The Tao of Willie: A Guide to the Happiness in Your Heart”, p.53, Penguin
http://www.azquotes.com/author/10736-Willie_Nelson