Left 4 Dead/Heartwarming


 * From The Sacrifice:
 * In Left 4 Dead 2, if you leave the safehouse to defib a Survivor, in a Versus round, you earn the "Heartwarmer" achievement.
 * In The Sacrifice, Francis goes into Sincerity Mode and confides in Louis that he has Insulaphobia, the fear of islands. Louis offers to "Watch his back" when they reach the Florida Keyes. They then proceed to psyche themselves up by saying things like "Punk-ass Island BITCH, y'all better watch your back!"
 * The entirety of The Sacrifice is this as you see the how the characters from the first game have months later all formed an incredibly deep friendship.
 * "Y'know all those things I said about you Ellis? I was joking..."
 * Doubles as a Tear Jerker, since Nick will only say this when Ellis has died.
 * The first time you finish the last campaign of any given game, especially if you played through the campaigns in order. This is the moment when you can truthfully say that Left 4 Dead is a modern-day Odyssey, not just a game about zombies.