Off the top.
Yo moma jokes in a galaxy far far away. A space chase (that was central to the plot btw) that could've been solved by having a Star Destroyer lightspeed ahead of the Raddus. General Hux shooting at the abandoned base instead of the escaping Raddus with the Resistance leaders on board. The weight of ships somehow effecting their speed capabilities when it doesn't.
Admiral Ackbar being killed off like he was a nobody and just so RJ could replace him with Admiral Gender Studies.
Admiral Gender Studies emasculating Poe. Gender Studies being able to destroy the Supremecy by crashing the Raddus into it at lightspeed. A lore breaking plot hole.
Ghost Yoda destroying the ancient tree with a lightning bolt.
Diversity hire Rose Tico. Nuff said.
Finn being reduced to a racist stereotype.
The entire pointless Canto Bight subplot.
Killing off Snoke in a way he shouldve saw coming and like he wasnt all that important to the story. Just for the sake of "subverting expectations".
Untrained Liea Poppins in space. Liea automatically siding with Gender Studies against Poe before knowing the situation.
Emo Ren's motivations for turning to the Dark Side being less than compelling. Note Anakin's turn in comparison. Emo being overwhelmed by Snoke's guards when he couldve just froze them in place. Emo going shirtless for the sole purpose of pandering to a female audience.
Rey being untrained. Rey mastering the Force in seconds by Force Downloading Snoke's training from Kylo Ren, as retconned in the novel.
Rey and Kylo supposedly being a new more powerful breed of Force Sensitives, in direct contradiction to what was established in TFA i.e. Kylo acknowledging that he's not as powerful as Darth Vader and therefore Luke Skywalker as well.
Luke wearing ceremonial Jedi robes long after he had give up the Jedi ways. Luke breast feeding from an alien creature with humanoid nipples. Luke nearly murdering his nephew in his sleep, as his first reaction to realizing that Kylo was having evil thoughts (in direct contradiction to what is shown in the OT). Luke as a deadbeat who abandoned his family and friends when they needed him most (also in direct contradiction). Luke not mourning Han's death, even for a second. Luke not having a legit action part. Luke dying like a punk.