Besides educating half the world as to what a craniotomy and acholecystectomy are, Grey’s Anatomy is widely revered for its many on-screen relationships, both platonic and romantic. As many TV medical dramas often do, Grey’s Anatomy introduces many different pairings throughout its lengthy run, some of which withstood the test of time, while others do not.

We have our famous couples, such as Derek and Meredith and Mark and Lexie, but how about the “what-ifs” of Seattle Grace? There were numerous flings that should never have aired on television, be it due to toxicity or incompatibility. Meanwhile, some instances of on-screen chemistry were never explored beyond a lingering look or a single steamy make-out session. These are the couples that never were but should have been, away in some alternative universe.

Miranda Bailey / Richard Webber

From the get-go, Miranda and Richard always had what we would consider a complicated relationship. Firstly, Miranda was Richard’s main confidante and advisor, especially during his difficult divorce from Adele. Whenever Richard steps out of line, if not his wife, Bailey is the next person to call him out.

Even during work hours, the two of them bicker back and forth like an old married couple, and whether it was intentional or not, the Grey’s writer’s room certainly incorporated some suggestive dialogue and some long, lingering glances at times.

Izzie Stevens / Denny Duquette

Technically, Izzie and Denny’s relationship did leave the launchpad, but it crash-landed immediately after. We wouldn’t say it “didn’t” happen, but it also didn’t did happen… for obvious reasons. In hindsight, Izzie’s sweet engagement to Denny didn’t last longer than a cup of coffee, plus it had one of the most heartbreaking send-offs of any Grey’s pairing.

Denny gets a cut LVAD wire and Izzie gets months of depression as well as a broken heart that never truly mends itself (oh, and metastatic melanoma, did we mention that?). If they’d been given a better start, Izzie and Denny would have been together forever — of that, we’re certain.

Mark Sloan / Callie Torres

In the fourth season, while attempting to bury her feelings for Erica Hahn, Callie enters into a friends-with-benefits agreement with Mark Sloan, who’d been dubbed Seattle Grace’s resident “man whore” by his colleagues. Later down the line, the fling results in Callie getting pregnant with Mark’s child.

Not to mention, Mark and Callie’s chemistry was off the charts, so if their phase of hooking up to redirect their feelings for others had blossomed into something more, we wouldn’t have been opposed to a short-term of Mark and Callie’s commitment. However, it wouldn’t be able to last, since Lexie and Arizona are their respective soulmates.

Lexie Grey / George O’Malley

Almost every TV show in existence has the one token ‘awkward’ couple — and that would be Lexie and George. When she first arrives at Seattle Grace as the half-sister of Meredith Grey, there’s a bit of commotion amongst the higher-ups, namely Derek and Mark. When she finds out that George, her fellow intern, failed his intern exam and must repeat a year, Lexie agrees to keep his secret and the pair become practically best friends.

Later down the line, they start renting an apartment together until George’s tragic death in season six. Lexie convinces herself that she’s in love with George and persistently flirts with him, but he rejects her, more concerned with the future of his career. It wouldn’t have worked long-term, but it might have been a nice stepping stone to something better.

Addison Montgomery / Tom Koracick

There have been countless times that MerDer fans wanted Addison gone for good, but no matter how she stood in the way of their happily ever after, no one could ever hate her. In fact, everyone rooted for Addison to find love after Derek, which she does in the Grey’s Anatomy spin-off series Private Practice.

Although Tom isn’t the man that Addison chooses in the end, if she’d have stayed on at Seattle Grace instead of moving to L.A., we’d wager that Tom Koracick would be her next in line. Especially after Derek, as proven with Alex and Mark, Addison has a soft spot for bad boys, and that perfectly sums up Tom’s personality, although he’s certainly a sweetheart behind all of it.

Alex Karev / Meredith Grey

Once Derek and Cristina exit the show, Meredith begins to confide in Alex. It’s no secret that Alex and Meredith were close from the beginning; Alex might have had drama with Izzie or hatred for George, but he could never bring himself to dislike Meredith. Once Cristina left, Alex stepped up to become Meredith’s “person,” just as she does for him.

Although we’re content with Alex and Mer staying friends, if things hadn’t worked out with Derek and Izzie for whatever reason, these two would certainly fill the void in each other’s lives. It wouldn’t have been true love, we don’t think, but it could have been something genuine that helped both of them through the hardest of times.

Jackson Avery / Cristina Yang

Introduced in season six, Jackson Avery becomes a surgical resident at Seattle Grace when it merges with Mercy West. Although Avery had a handful of romantic partners, he fell for Cristina Yang primarily after arriving at the hospital. During a house party, Cristina and Jackson share a steamy kiss, but Cristina eventually breaks it off with him.

Things never go further than that, as much as Jackson probably would have wanted it to. We’d much rather have Cristina with Jackson than Owen (because what was that all about?), but it wasn’t in the cards for her future. Let’s not try and deny the fact that Cristina and Jackson’s kiss was one of the hottest in Grey’s history.

Addison Montgomery / Alex Karev

Another short-lived relationship occurs in the third season between Alex and Addison once the latter punishes him for almost getting her arrested by assigning him to her fertility unit. After some sexual tension, Alex and Addison share a kiss at Joe’s bar before getting down to business. Addison expresses her desire for a relationship, married, kids, the whole bit… but Alex isn’t ready to commit, so things eventually fizzle out between the two of them.

That being said, there’s something tempting about a potential relationship between Alex and Addison, as it gives us those “so wrong, it’s right” vibes. Realistically, Addison would have been too much for Alex to handle; she’s far too high-maintenance for someone younger than her, so it’s probably for the best.

Owen Hunt / Callie Torres

We’ll get this out of the way immediately and say that, honestly, no one likes Owen Hunt. He gets somewhat more likable as time goes on, but that doesn’t make up for how unbearable he is in the beginning. In Meredith’s dream of an alternate universe, Owen has married Callie and they have three children, although they are not happy together at all.

That’s a glimpse into the future of Owen and Callie’s potential relationship, which clearly wouldn’t have worked out. That being said, Owen and Callie do have good on-screen chemistry as compatible friends, so it isn’t far-fetched to have assumed that they’d work out as lovers. We’d safely established through Callie’s relationship with Arizona, however, that she was ready to settle down with a woman.

Addison Montgomery / Callie Torres

Although there are never any explicitly sexual or romantic scenes between Addison and Callie, that doesn’t say there couldn’t have been. Yes, Addison is straight, but just as Callie had awakened her bisexuality through a crush on Erica Hahn, the same could have happened to Addison through a crush on Callie. After a marriage that didn’t work out, it wouldn’t be the most unrealistic turn of events.

After Hahn leaves, Addison is there to comfort Callie for a brief time before she returns to L.A., thus if things had turned down the romantic route during those moments, we wouldn’t have complained. Besides, both Addison and Callie are attractive women, so that’s a recipe for a steamy fling at the very least.