I'm really doing you the greatest favor of your life.
"It was the greatest favour she did in my life!"
"I would consider it the greatest personal favor."
He had done her the greatest favor possible.
He begged her to hear him explain himself, as the greatest favour she could show him.
The gruffest voice and so the greatest favor of all.
His face radiated happiness as though I had done him the greatest favour.
Alcohol did me the greatest favour, which is that it brought me down to earth.
Strange, he thought, how my greatest enemy did me my greatest favor.
"He did us the greatest favor," she said.