Who said "I have learned that gratitude is a weakness."?

This quote is attributed to Lannister.

I have learned that gratitude is a weakness. - Lannister

"I have learned that gratitude is a weakness."

Lannister Gratitude

"A Lannister always pays his debts."

"I am the god of tits and wine."

"You are an awful man."

"I drink and I know things."

"Gratitude makes life richer."

"A grateful heart is a happy heart."

"Respect those who came before us."

"Life's greatest treasures are the people we love"