Hmm... You said ONE, but I hope this counts because I've got a "grouping". My favorite scenes to write and to read are anything with intense emotions!
- A reunion after a long time, either between family members, or friends who were looking for each other, or a couple that had been separated. 1b) Doesn't have to be a happy reunion. It can be like, two people meeting after having left on a super bad note and now they're all, "I've finally found you
"
- When justice is served
- Or even when revenge is served, because emotions are still running high
- Huge dramatic arguments where one or the other says something they shouldn't have, and it ends in silence. Soap operas can be great
- Any joyous scene that could also serve as a memory a character recalls as a moment of peace, or happiness
- Twists, because they're a huge, "OH NO!" moment. It's great when the characters realize they gone done miscalculated.
Any of these scenes can be done poorly, so it's really dependent on how I manage to write it, and, of course, the lead up to the payoff. If there's no proper lead up, I won't feel the payoff the way I should. If there is, then these scenes always serve as a milestone for me, and encourages me to write so that I can get to them.