Applejack and Rainbow Dash ended up together in the main universe - through the portal, it was Applejack and Rarity. It's a fair question who made the right choice - from the sidelines, the other Rainbow and Rarity wonder if it was them.
Pinkie and Rarity throw a party to announce their relationship. Pinkie asks Rarity on a date, getting the rest of their friends to help plan it, all while Rarity and Pinkie try to help Fluttershy and Rainbow deal with their feelings for each other.
Flash Sentry doesn't know when Pinkie Pie became his best friend, but nothing is ever certain whenever she's around. The only thing he can expect is that her company is always a bright spot in a dull world, and that might be enough for him.
It's New Year's Eve and Rainbow Dash finds out that Applejack has been in love with somepony. Now this wouldn't be a problem if Rainbow Dash didn't have a crush on Applejack.
Nightmare Moon has always felt negative emotions, but if there was one thing she didn't expect it was that she; the part from Luna's negative feelings, would feel a positive feeling towards the unicorn who defeated her: love.
Memories of what happened during the Battle of the Bands haunt Twilight's mind, making her feel down. But maybe there is a pony that can help her feel better.
After Princess Twilight declined becoming the sole ruler of Equestria, her life returned to normal for the most part. It is while she is thinking about who gave her the advice to decline the role that her feelings come to the surface.