24/Heartwarming

"Mason: Believe it or not, I used to want to be a teacher. A long time ago. You know why I didn't? Because DoD offered me more money. That's how I made my decision. So I made myself miserable, and I made everybody around me miserable. For an extra five thousand dollars a year. That was my price. ...You know, Michelle, I'm not a big advice giver, but under the circumstances, don't wait around for your life to happen to you. Find something that makes you happy. Do it. Because everything else is just background noise."
 * In the first season, then-Senator David Palmer angrily confronts Jack Bauer who he's been wrongly led to believe has been trying to kill him. Jack furiously explains that both he and his family have nearly died because Jack has been working to save him. The look of shock, embarrassment, and understanding on Palmer's face are priceless as he realizes that Bauer is a patriot who has saved him and his family. It is the start of a friendship that would be central to the show for the next several seasons.
 * David Palmer resists the temptations of one his staffers and proves (somewhat sadly) that no real President will ever have that kind of character.
 * George Mason's speech to Michelle in Season 2.

"Jack:"
 * In Season Seven, Jack's World of Cardboard Speech to the imam as he lays dying in the FBI headquarters hospital.
 * The entirety of the season 7 finale.
 * The end of Season 7, in the White House, when an exhausted Allison Taylor allows herself a moment of weakness, confessing to her former Chief of Staff (and close friend) Ethan Kanin, "I've lost everyone." Ethan says simply, "Not everyone," and she correctly concludes that he is un-resigning. The look of dawning hope on her face is simply magnificent.
 * Jack's last 2 calls at the end of Day 8.
 * The last conversation between Chloe and Jack.
 * George Mason patching things up with his estranged son, John.
 * Jack and Chloe's final interaction in the series finale. Chloe's (very likely real) expressions sell the entire scene.