The Witcher/Heartwarming

The good ending of the quest "Beauty and the Beast" in the first game. Carmen is moving mountains to find a remedy to cure Vincent, a werewolf. Geralt finds three remedies, and when the first two don't work, Geralt mentions the third: true love. Carmen is convinced that Vincent doesn't love her because she's a whore, but when Geralt goes to Vincent and tells her, he's willing to give it a shot. It works, and they get married.
If Geralt decides to cure Adda of the striga curse again instead of killing her, there will be a small cutscene in which Geralt says that although witchers are renowned for slaying monsters, they (or at least, he) take far more pleasure in lifting curses and breaking spells on people.
A potential solution to "In The Heat Of The Day" can be one too: If Geralt defended Abigail against the mob in Chapter I, she suggests poetry to put Alina to rest. Dandelion whips up a poem at dusk, and after Alina understands that she's dead and a noonwraith, her sister (now a nightwraith) shows up, and begs forgiveness for killing her. Alina forgives her, the two reconcile, and Alina moves on to the afterlife. And if you completed "Hunting the Wild Hunt" and asked for the Wreath of Immortelles, you can put Celina to rest too.
Triss promising to help Geralt find Yennefer in the second game. Doubles as a Tear Jerker, since she's obviously heartbroken about it (being in love with Geralt since forever and all), but she's willing to suck it up for her friends.