- Batman's first appearance in the movie, when Emmet stops for a quick chat with him. It's not clear what happened to the rest of Batman's friends between this movie and The LEGO Batman Movie (if that was even canon) but it's hinted to be something bad.
- When Sweet Mayhem kidnaps his friends, Emmet tries to convince the rest of Apocalypseburg to go with him on a rescue mission and gives a pretty good Rousing Speech. They slam the door in his face in response.
- Rexs backstory: Hes Emmet from the future, having been lost under Finns familys dryer and was left there for years. Feeling abandoned and forgotten, he made himself into a tougher, seemingly more mature self and decided to go it alone since he felt he could no longer count on his friends.
Rex: You came back for him?
- His reaction when he sees Lucy come to Emmet's rescue. It's the only time his voice momentarily sounds like Emmet's voice.
- How resigned Rex is to his fate when he begins to fade from existence. He even makes light of it, sounding almost relieved that he's dying.
- Possibly justified, as Rex isn't actually dying. He's becoming an alternate timeline version of himself and, given the context, that's a Good Thing.
- After Lucy realizes that the Systarians were Good All Along, she tries to stop Emmet from destroying the wedding. Rex had already put the idea into his head that Lucy was brainwashed, so he's reluctant to believe her sudden change of heart. To twist the knife in further, Lucy tries to get Emmet's trust by apologizing for trying to make him harden his heart, and opens her own to him. This only makes Emmet more certain that she's been brainwashed because she put up this act for so long that being "dark and brooding" is all he knows her for.Lucy: Stop! Emmet, you don't know what you're doing!
Emmet: This isn't the real you!
Lucy: This is the real me! The truth is... this [my blue and purple hair] is my real hair. I used to sing and dance, and have colorful hair and I even loved "Everything is Awesome!"
Emmet: [still reluctant] No, no! You would've told me! You hate that music! It isn't you!
Lucy: Yes, I darkened my hair with marker because I wanted people to think I was cool and grown-up! And then I tried to change you into someone tough too, and I was wrong! I like you the way you were! Sweet, innocent, kind!
Emmet: [beat] The real Lucy would never say that.
- If you really stop and think about it, a lot of the catastrophic happenings in the film were caused by seemingly mundane decisions and twists of fate. The Systar System's residents' poor communication lead to the people of Bricksburg thinking that they can't be negotiated with, resulting in their animosity, and the latter's repetitive jumping to conclusions only replaying the vicious cycle. On a smaller note, Lucy not being more honest about her true self with Emmet during the five years of their relationship, as well as her wish to see Emmet mature, results in our protagonist not only taking the advice of the seemingly supportive Rex(who's actually a future him who wants to destroy most of the universe out of vengeance) but refusing to believe Lucy when she insists that the Systar System's residents were Good All Along. Not to mention, the fact that Rex existed in the first place was because he was left to die underneath a dryer for several years while his friends partied with everyone, presumably under the belief that Emmet was still safe in Apocolypseburg. The reality that the smallest decisions can result in such immense consequences is a prevalent theme in this movie, which is a surprisingly realistic and symbolical lesson in something like the Lego Movie franchise.
- If you read this conversation as a parallel for the real-world argument between Finn and Bianca, then you have a young girl who looks up to her older brother having to see him suddenly act like someone she doesn't even recognize. Despite her best efforts to reach out to him and assure him that everything will be okay between them if he just listens, he's too stubborn and angry to hear her out. Poor Bianca...
- Alternately, it can be read as a conflict between two sides of Finn's personality: The one feeling pressured to be "tough" and "grown-up" (probably by his teenage peers) and the one that realizes that the way he's acting isn't right. The "tough, grown-up" side wins.
- Finn breaking Biancas sets when she just wanted them to play together again.
- The Master Builders and Systar inhabitants being thrown into storage, and then all singing about how everything is NOT awesome.
- Queen Watevra & Batman during Ourmamageddon. When Emmet shatters their wedding cake altar, Queen Watevra is shattered as well. We then see Batman show more despair than he ever has while he tries to hold on to the last piece of her face. She's sucked into the Bin of Storage, and Batman desperately gathers up her pieces while calling for her not to leave him.
- Later in the sad song, Everything's Not Awesome, he sings that love isn't real and he just wants to eat carbs in despair, pass the ice cream.
- More heartbreaking considering his other romances in the LEGO films. The LEGO Movie? Ends his relationship with Lucy so she can be with Emmet. The LEGO Batman Movie? His crush on Barbara Gordon ends up unrequited, something that even he eventually realized. And given how Batman is aware of his past incarnations who have either dumped or betrayed him,Lucy and Barbara were basically salt thrown into the wounds. In this movie? The first time he has ever felt genuine love for someone who loved him back and she's broken apart in Ourmamageddon, leaving him widowed at his wedding. Just... damn.
- On the real-world side of things, there are some hints that Finn and Bianca's father isn't doing his part in raising the kids: President Business, his stand-in in The Lego Universe, runs off to go play golf during the opening of the film, despite the obvious crisis surrounding him, which likely parallels some real-life incidents in the household. Later, he refuses to even get involved in the conflict between Finn and Bianca, leaving it up to their mother. His lack of interest is clearly having an effect on Finn, too.
- Rex brutally beating Emmet in Undar the Dryar to the point of incapacitating him, all while taunting him about how his friends had failed to save him. The look on Emmet's face, just before Lucy (thankfully) arrives, is heartbreaking as though he really believes in that moment that his friends never truly cared about him.
Tear Jerker / The LEGO Movie 2: The Second Part