"...What are you gonna do Ardyn? Shut me out like you made us do to our grandfather? I'm surprised the old man hasn't keeled over and died of neglect considering the hell you intentionally him through. But hey, what do I know? I'm too young to know what I'm talking about. I should just mind my business and do my own thing, right? Is that the reason why I'm over here as healthy as I can be, while you're over there dying of extreme exhaustion from overworking yourself? Do you honestly think for a second that you enslaving and martyring yourself to an imaginary cause - which was born out of a misconception gone wild, mind you, will do anyone any favors?! Pathetic! Maybe for your enemies and the countless leeches you surround yourself with, sure. But for us... you'll be doing more harm to this family than what those damn Pokemon Hunters did to our parents and grandmother! Y'know... The more I look at you, the more embarrassed I feel... To think this is what I aspired to be. A withered-out gray-haired dumbass with his head so far up his own asshole, he thinks he knows best just because he's slightly more talented and dedicated than the rest of us. For someone who says they deeply care about their family, you're doing a shit job at showing it... as always. Maybe you never cared to begin with... Maybe... you were using our grandfather to further your own ends. You wouldn't be the first person to try it. But hey, kudos to you! Unlike the rest of them, your kiss assery succeeded. I hope that fucking yourself over and pathetically dying from meeting menial expectations in exchange for all that power was worth it Ardyn. I would never want to be in your position. I have more common sense than that. Ironic, for someone of your "supposed intelligence". ...You make me sick, really."

Yeah... this speech happened during the year Elio took a break to fully and properly recover from the wounds he suffered during the final Unovan rival battle against Varyus. It was a multilayered insult-truth bomb combo that not only hurt Ardyn, but Elio himself. Made even worse when Elio was utterly cold and detached throughout the entire thing after Ardyn harshly rejected him.

He was done.

He never thought that he would reach this breaking point with anyone he cared about. But the combination of said rejection, seeing the damage Ardyn was causing not only to himself but those around him by not giving his body a break from all the expectations he's supposedly "meeting", and the violent eruption of Elio's festering bottled-up hatred that was born after he developed his emotional foundation and stemmed from years of self-isolation and developing a perfectionist mindset via the "Argentium Perfectionism" mentality - which he thankfully discovered to be a toxic philosophy, no matter how well-intentioned Ardyn and the other older siblings were in perpetuating it since it was slowly destroying the family and emotionally paining his grandfather, had eventually caused him to just... really snap.

After that delivery, despite his normally indomitable will, the silver-haired trainer felt nauseous and just... emotionally broke down in private; not only for being out of character but also for breaking his personal promise of not reverting to his emotionally-stunted self. Though it didn't take long for him to recover since he knew it was a necessity. Ardyn himself was initially furious; but after much convincing by his secretary, certain board members, and co-workers to take a few weeks off, and later having a heart-to-heart with his grandfather, Wolfgang - who explained how truly content he was that Ardyn finally opened up to him after more than a decade, something that really blindsided the former, he had time to deeply reflect and realized that everything Elio said about him was right; typically, the realization led to his own emotional breakdown - but unlike his younger sibling it took some time, proper therapy, and a bit of medication to recover. For a time, things were awkward between the two of them since they weren't on proper speaking terms; however, it also became an opportunity for Ardyn to open up more and spend time with the rest of his family. Only after Elio decided to continue traveling that the two of them properly made up.

Elio prays he would never have to say anything that disgusting to his other friends and siblings.

Probably anything she ever said to any Team Flare member after she left the organization.

There's no doubt that, even if Briar tried to go unnoticed by the Interpol, sooner or later she would end up meeting someone who worked in Team Flare with her. Someone that recognized her and tried to speak to her, but Briar, who was incredibly afraid of being discovered by some agent, ended up acting cruel and heartless towards any former member of Team Flare.

"Why are you speaking to me? I never cared about you. Leave me alone."
"We are not friends. We were NEVER friends."
"You were all part of a business for Lysandre, and for me as well. So don't think just because we worked together in the past you can come and talk to me like we're buddies. Get lost."

And the truth is that she cared for Team Flare. But maybe the whole experienced caused her to become colder, and knowing that the Interpol might get her at any moment, she prefers to look out for herself before having to look out for another Team Flare member. So sometimes she has to hurt people in order to achieve it.

Odd, for a short period of time after his dad died, was very callused/spiteful in how he interacted with many people, so he said quite a few things to people he cares about he regrets

One of the worst things he said was to his friend Linus (a smarmy opportunist and most recent inheritor of his family's connection to Yveltal), whom had gotten in an argument with Odd over the things he was doing to try and find who was responsible for his father's death (something Odd felt particularly vindictive about in regards to Linus, as they hadn't proved themselves to be any paragon of morality in the years Odd had known him). The fight escalated, with Odd ending it with this;

"You know, maybe you weren't so wrong, what you said all that time ago; maybe you are better off dead."

Ooh that's a tough one... I guess one of the more memorable ones he had said was to his Mom back when they were still arguing about Tyler's life choices. Since admittingly, Tyler is really reckless, and his mom is very protective and was helicoptering him a lot ever since he was a rowdy kid. So of course she hated that he was a Trainer back then then during an argument about him staying and quitting being a Trainer after nearly dying in Hoenn (Long story, involves Rayquaza-), Tyler spouted "You know what?! I wished I DID die back there, because at least in hell I wouldn't have a Mother who bitches at every little thing I've done in my life! Its like you've never respected me!" That caused tears from both parties and he left the house for a good while, but after some convincing, he and his Mom sat down and had a heart to heart. His Mother apologizing for always controlling what he did in life, because she was an Ex-Rocket grunt, and she didn't want him going down that path in life like she did. And Tyler apologizing for what he said and never taking her feelings into consideration. His Mom slowly but surely respects his choices more and supports him more, and Tyler began visiting home more often after that. Not after a lot of hugs and tears--