Rodimus: "When you became Optimus Prime—when you assumed the title—the world didn't know the truth about Nova and Nominus and the rest. Back then, being a Prime meant demonstrating—no, actually—embodying certain standards of behavior... it meant decency and integrity and—and morality—and all sorts of things that chancers like me pretend are unfashionable, because deep down they scare us... and they scare us because we try to live our lives by them but we can't. Well, guess what? You can. You can and you do—every day. Thanks to you, the word Prime still means decency and integrity and morality. Listen. The world will always need a Prime... but only if that Prime is you."
Dark Cybertron 10
Chromedome talks about Rewind, confirming that he didn't erase his memories of his lost love.
Megatron, of all 'bots, having a Heel Realization as he reflects on how he lost the war the moment he lost sight of winning the hearts of the people.
Dark Cybertron 11
The entirety of Megatron and Bumblebee's final conversation, as Bumblebee appeals to Megatron's better nature to spare the broken Galvatron. The amazing part? He succeeds.
Bumblebee:Good, bad, friends, enemies... if there's one thing I've learned since Metalhawk and the others came home, it's that the world's a lot more complicated than that—and so are you. So let him live—let him join us.
(Megatron relents and offers Galvatron his hand)
Bumblebee:See? We're stronger together than apart.
Rodimus chooses to get the wounded to safety rather then charge into battle, despite Cyclonus (one of said wounded) arguing over the logic of taking the later option.
"Right now, I'm the Captain, and you're my crew. Whether you're a Lost Light-er or not, I'm responsible for you. It's not logical, but it's right. You know me well enough by now, Cyclonus. Heart before head, every... single... time."
Megatron calling Bumblebee his friend.
In the end, Optimus and Megatron decide that if they can forgive Shockwave after everything he's done, than they can forgive each other and move on from the war.
Optimus Prime:"On behalf of everyone you helped — every outlier you tutored — every function runt you took under your wing — every naive young law enforcer whose eyes you opened — and every miner you made sure was safe — Senator Shockwave, I promise you —"
*cue both Optimus Prime and Megatron dramatically raising their weapons against Shockwave*