During the Game of Thrones season 7 finale, fans couldn't help but notice that Tyrion Lannister looked especially sad when he discovered Jon and Daenerys were having sex on the boat - and fans had a lot of opinions about why exactly the youngest Lannister wasn't happy about the pair's romance turning physical.
We're breaking down the most popular theories below and they're all interesting to consider; however, if you're short on time, you can jump to page 2 of our write-up for the REAL Reason Tyrion is Bothered by Jon and Dany's Romance.
It's easy to assume that Tyrion, like many men who crossed paths with Daenerys on Game of Thrones, is love sick for the Mother of Dragons - and that is one possibility. However, throughout the time that Tyrion has known Daenerys, he's never expressed romantic feelings towards the Queen - regularly reinforcing that he has joined her side because he believes she is the ruler that Westeros needs. It's certainly possible that Tyrion's feelings have changed and that he has begun to develop romantic feelings for Daenerys or worries that, with Jon becoming the Queen's close confidant, the Hand's role will be in some way reduced. In a world of incestuous relationships, Tyrion wanting to be with Daenerys is actually less strange than the reality - she's having sex with her nephew. After all, George R.R. Martin's original draft of Game of Thrones featured a love triangle between Arya, Jon, and Tyrion - so it is possible the showrunners have altered that original idea into a Daenerys, Jon, and Tyrion love triangle. That said, the most "obvious" answer isn't always the most accurate.
If you need a refresher of Tyrion's reaction, you can watch the full boat scene - HERE.
Another reading that some fans might champion is that Tyrion had a change of heart after hearing Cersei is pregnant again. Tyrion made it clear that, more than any thing else, he regretted his (albeit indirect) role in the death of Cersei's children. In that context, the ominous look we see from Tyrion could be intended to suggest that he's plotting to betray Daenerys - and that Jon adds a new layer of difficulty for Tyrion to navigate. Still, while it's certainly one possibility - the move would sidestep a carefully laid trajectory for Tyrion's character over the last several seasons with only six episodes left. That dramatic of a shift seems unlikely - as many of the characters are starting to fall into their legacy positions (see: Sansa and Arya coming together in spite of Littlefinger's meddling) rather than make dramatic shifts for the sake of plot twists.
The reaction could also suggest Tyrion knows Jon's true name and identity and is wary of how that news will play out once Jon, Daenerys, or practically anyone else finds out - especially given that Aegon Targaryen is the true heir to the Iron Throne. That said, there's little reason to believe that Tyrion has that information - given the way that he's talked about Jon in the past as "Ned Stark's bastard" (not to mention the fact that Tyrion was actually the person who planted the seed in Daenerys' mind that Jon was interested in her). It's certainly possible that Tyrion, who has always been savvy about discovering and keeping secrets, has known Jon's true identity all along - or recently found out; still, there's no evidence, no hints, nor foreshadowing to suggest this is the case. Jon Snow's parentage is the series' biggest secret - and one of seismic importance in both the story and how Game of Thrones ever made it to television. If Tyrion knew this secret, it would mean other people had to know - which would undermine Ned Stark's selfless act, pretending that Jon was his bastard rather than his nephew - a lie that was ultimately a burden on his marriage and and a smudge on his otherwise honorable life.