How did Rey learn the force so quickly?
Okay, so this mystery is still unclear even after The Force Awakens and The Last Jedi. Rey is a nobody and a loner, but suddenly she's an expert pilot of the Millennium Falcon and then later gets in the head of Kylo Ren, who has had Jedi training. Never mind that she gains the Jedi Mind Trick. But in The Last Jedi, she pretty much has a few days of training with Luke Skywalker and then becomes a Jedi master in basically 48 hour's time. Luke was on Dagobah with Yoda for who knows how long before he became able to harness his powers, and even so, he was not as strong as Rey in such a short amount of time.
What is that weird space leprechaun?
Canto Bight has seen its fair share of criticism, but one thing that we can't figure out is the weird little, drunken space leprechaun who pumps golden treats into BB-8 like a slot machine. It's understandable that those coins end up being used as a weapon later on during the escape scene, but what the heck? Throughout the movie, BB-8 proves that he's more than just a cute little droid, he kicks ass and rises to the occasion. So, why have a drunken leprechaun molest him when he could've figured out a cooler way to take out those guards on his own? It just seems weird and out of place.
Why is the milk green on Ahch-To?
Now this scene should not have been in the movie at all, and from what we can tell, it's a throwback to the blue milk that Luke drinks with his aunt and uncle on Tatooine. But why is the milk green on Ahch-To and why does it come from a giant 4-teeted sea creature? The scene sticks out like a sore thumb in The Last Jedi while searing the image of the new sea creature into the memories of millions of Star Wars fans. This may very well be the biggest unexplained mystery in the movie.