I love the twist reveal in Guardians of the Galaxy 2 because one, I didn't see it coming, and two, I love Quill's immediate reaction. Most stories have the MC take longer to process or decide to shut down the villain's operation without explicity trying to kill them. Even with what Ego did, he's not evil, just devoid of any empathy, but understandably, Quill's twitch reaction is to immediately try to kill him.

I also like how it justifies Thanos being able to goad Quill in Infinity War. Usually at best, it's plot convenience, and at worst, it's totally against character, but with Quill, it was totally in character for him to immediately take the bait based on his reaction to Ego. It was definitely established that he has a button.