Yukiko telling off those reporters near the end of her Social Link series. It was real nice to see her have a backbone to something like this.
In the True Ending, the Main Character, rather pissed off at the boss and suitably powered up by the events right before the fight, takes off his glasses, throws them away, summons his persona, and blasts the everliving hell out of the boss.
And that was his response to Izanami hammering him with an insanely powerful spell several times in a row. Which had no effect whatsoever.
The glasses weren't an evoker of any kind, and had nothing to do with summoning Personas. The glasses let them see through the fog, and him throwing them away symbolized that he didn't need them anymore, because he'd discovered the final truth (also, the ability you're using at the time is called "Myriad Truths"). Still CMOA, but for entirely different reasons.
It's implied the glasses also protect the wearer from the health effects of the fog. In other words, he doesn't fear death, even the goddess of it herself. Especially since since he was on its brink minutes earlier.
And on top of all that, he earns a perfectly happy ending. In a SMT game.
Kanji has his CMOA prior to the game, in this troper's opinion. Everybody thinks he's caught up with a local teenage biker gang, but as he keeps trying to explain, what really happened is that he beat the shit out of the whole gang. Why? They were keeping his mother from sleeping at night with all the noise and racket they made.
And to rub salt in the wound, he did it all with a shield he bought from Daidara's Metalworks. No, really. Ask Daidara during Kanji's disappearance.
Speaking of Kanji...he doesn't get his Persona just by coming to terms with his Shadow. He gets it by punching it out and then coming to terms with it.
"C'mon... get up. Anyone who looks like me, I know they ain't so weak that they can't take a punch."
Most of the Scooter follow-up attacks are also funny, with Yosuke simply crashing right into the enemy, Chie just ramming the enemy really hard, Yukiko panicing jumping off as & cowering in fear as her bike continues on its own and careens into the enemy. The two party members who don't have scooters aren't left out, with Teddie casually roller skating in & hitting a drill kick, and Kanji riding his bicycle before jumping off & slamming it into the ground. The only which isn't funny is Naoto's, but hers is just badass.
Another one for Teddie: When after realizing his true nature, he decides to get over that fact for Nanako, overcoming the feeling of failure and monstrousness that he had fallen into, and thus, awakening to his Persona's real power.
In one of Yukiko's later S-link scenes, she is getting harassed by a sleazy TV producer and his crew,who wanted to take advantage of her family inn's worsening financial status by pressuring her into agreeing to make a tabloid-style show about the inn. Her response to the TV crew? She snaps and puts them back in their place, making them stand down and leave promptly, proving that you should Beware the Nice Ones indeed.
Made even better when how Yukiko's S. Link is about gaining confidence and preparing to leave Inaba, then she realizes the inn and everyone in it is what matters most to her and she stands up for them.
Not to leave out what probably is the greatest of them all: "Children of man... well done!"
TWO hits, actually. One kicks in when any one of the party members is about to take a blow that would knock them out. The other one is a full-on revival for the Protagonist when HE goes down. You get THAT ability by maxing her social link. There's nothing like taking a second one of Margaret's Megidolaons and getting your butt pulled out of the fire by that move when you're in a relationship with Rise: equal parts Crowning Momentof Heartwarming and Crowning Momentof Awesome.
Naoto's critical hit certainly counts. Strolling up to the enemy while shooting them three times before rearing back and planting her foot in the enemy's ass. There are quite a few awesome critical hits in the game, but Naoto's takes the cake simply because of how casual she is about it.
Kanji snapping everyone out of a Heroic BSOD after Nanako's hospitalization.
The MC gets a notable one. The rest of the group are contemplating throwing Nametame into the TV for Nanako's "death." After trying to defuse the situation and convince them that they don't have the whole story, the MC finally loses his temper and shouts, "Calm the hell down!" And, of course, it works.
Yosuke: "Geez... How the hell can you stay so calm, man? Then again, that's why you're our leader..."
The MC gets another one in Golden when you choose to confront Adachi alone (because he's also now a social link and get it up to rank 8). Adachi will then shoot the MC barely missing on purpose. The MC doesn't. EVEN. FLINCH. The Jester then changes to Hunger link.
A very minor one at the very beginning of the game, when Mr. Morooka introduces you by calling you a loser, one of your dialogue options is to deadpan "You calling me a loser?" This not only raises your Courage, but also gives the player a satisfied feeling at putting King Moron in his place, even if only for a brief moment.
The Junes concert. While the scenes of the team doing their hardest to pull it together are hilarious, the fact still stands that they got it all together in just two days, with only one person besides Rise ever having experience performing in front of others (and that's Naoto, who admits she hasn't played in a piano recital in years). This is what the investigation team put together in the end. The game even notes that the team "became legends" as a result of this!
It's also a big moment for Rise, who shows just why she was such a popular idol in the first place when she's the one who's behind putting most of the actual performance together. She doesn't just have spirit, she has talent and know-how, and she gives a great pep talk before the gang goes onstage.
The Protagonist gets his motorcycle license after studying for one night. This may also apply to Yosuke, but it's unclear if he had been studying for the test before then. In comparison, it takes the girls several weeks to do so.