This one's obscure, so I'll give it to you first: that would be Edge/Rydia from Final Fantasy IV. Why pick such an old game for a pairing that needs to happen now, you might ask? Well, because they've released so much new stuff for it relatively recently, including sequels. Frustratingly, none of it (as far as I know) has expanded on Rydia's feelings for Edge and what they mean. In the original, they were ambiguous--she mostly turned him down or ignored him during the events of the game, but at the end, after the quest to save the world was over and she'd had time to mature a bit more, she approached him and he was the one who turned away out of awkwardness.
It appealed to me when I first played FFIV for a few reasons. One was that I liked both characters--Edge for his combination of entertaining hotheaded stupidity and genuine dedication, Rydia for the way she carried her baggage and how she could be both badass and vulnerable. Another was, as always, the chemistry: for such a small and insignificant couple of early '90s video game sprites, they struck an engaging balance between bickering and cautious affection. The last one was that I thought they had things in common they weren't admitting: specifically, both of them needed to grow up in some way--Edge because he'd been raised as a spoiled prince all his life and now had to take over a kingdom, Rydia because she'd grown up among monsters and still needed to figure out how to deal with human beings--and it would be fun to watch them do it together.
The remakes and sequels seem to have forgotten all that in favor of adding more jokes about what a big crush Edge has on Rydia. What I want is more mutual interaction between them, dammit.
Day 02 - What was your very first ship?
Day 03 - A pairing that needs to happen now?
Day 04 - The pairing with the most chemistry?
Day 05 - The pairing with the least chemistry?
Day 06 - The best kiss?
Day 07 - The most heartbreaking scene?
Day 08 - The pairing with the most baggage?
Day 09 - The most believable relationship?
Day 10 - Why aren't these two married in real life?
Day 11 - What is your dream pairing?
Day 12 - Who had the best wedding?
Day 13 - What is your favorite television pairing?
Day 14 - What is your favorite book pairing?
Day 15 - What is your favorite real life pairing?
Day 16 - What is the absolute worst pairing?
Day 17 - A pairing you thought would never work out, but did?
Day 18 - What is the cutest pairing?
Day 19 - A pairing you've rooted for since the beginning?
Day 20 - The "can't stand the sexual tension anymore" pairing?
Day 21 - A pairing you like and no one else understands why?
Day 22 - A pairing you hate and no one else understands why?
Day 23 - A crazy love triangle/quadrilateral that worked out great?
Day 24 - A crazy love triangle/quadrilateral that worked out badly?
Day 25 - A pairing that was/would-be adorable, but could never work out?
Day 26 - A pairing that you hated and ended up loving?
Day 27 - A pairing that you loved and ended up hating?
Day 28 - A pairing that you will never understand?
Day 29 - What ship had the best proposal?
Day 30 - Your favorite ship forever and ever and ever?