the least you can/could do
the least (one) could do
Something that someone ought to do; the very minimum someone should do. I know you're angry with your father, but he seems like he really wants to make amends. The least you could do is hear him out. A: "Thank you so much for the lovely card and wonderful bottle of wine!" B: "It was the least we could do after you took care of our pets while we were away."