Ezio's interactions with his wife and daughter, all of them. After everything that's happened to him in his life, seeing him take such quiet joy in spending time with his family just warms the heart.
At the end of the film, Sofia tells Ezio that she and Flavia are going to the market for the day. Knowing that he's going to pass away soon, Ezio decides to go with them. He dies happy, watching his family laugh as they go about their day, and we hear aloud his final letter to Sofia, telling her how happy his life with her has made him in his final years. Doubles as a Tear Jerker.
In the last scene a young Casanova Wannabe sits down next to Ezio and spends a few moments complaining about how boring Florence is, and about how he wishes he were in Rome, where he's heard there are plenty of girls. Just as Ezio is getting fed up with the youngster, the young man notices Ezio's chest pains and coughing. He promptly takes Ezio's hand, tells him to get some rest, and takes off after wishing him well; all while sporting a kind smile. A clear reminder of the young Ezio which makes the older one smile in recognition.