Note: Minion Quest: The Search for Bowser examples go here.
- Every time Mario and Luigi share a hug when they reunite after getting separated. These recurring hugs happened again in all games in the series except for Partners in Time.
- Also deserving of mention is their hugging Princess Peach after she is kidnapped in Teehee Valley (which you can repeat, even multiple times, if you let her get captured again). There's no unique sprite, so it's staged as just the Mario-&-Luigi-hugging sprite over top of Peach's, but it gives the impression of a Group Hug, which is very touching and shows how much the plumbers and princess appreciate each other's company and help.
- When either one of the brothers suffers a KO in battle, the one still standing gets an absolutely horrified expression, rushing over to the fallen one and carrying his unconscious body on his shoulders when he's attacked despite it causing a delay when he has to jump or use the hammer to counter-attack due to his weight. If the player chooses to flee during their turn (this too happens for the rest of the series), he first picks him in his arms and then runs away. This is an unexpected and innovative mechanic for an RPG, but it also shows how Mario and Luigi are highly protective of each other. No bro left behind.
- The little 'we're still in this, bro!' animations that play when one bro revives the other. They really do count on each other in a fight.
- When the bros are separated, either because they need to do so in order to progress or because of a scripted event in the story, only the brother you're currently controlling is shown in the pause menu you use to change your equipment or use items out of battle, while the other brother only appears as a silhouette and his passport picture disappears. If you go to the equipment menu and go change the equipment for the brother that you're not controlling, the other one will hold his brother's photo to show you and call out for him in worry. Mario in particular directly points at Luigi as he shows it to the player. It's like he's saying "Have you seen my brother?". Mario and Luigi get separated for just 5 seconds and they get already worry so much about each other to the point that they almost seem on the verge of thinking that the other brother has gone missing? Maybe they're overreacting a bit, but awwww...
- The remake adds a villager who asks you to buy three nuts for 72 coins. If you agree, he'll quietly whisper that he has enough money to buy his ma something nice.
- The relationship between the Mushroom and Beanbean Kingdoms is very heartwarming. Both Queen Bean and Princess Peach have high opinions of the other, and are both willing to drop everything to help the other kingdom whenever they have a problem. Even when things get tense, there's never the slightest hint of strife or xenophobia.
- Sure, they may be villains bent on attaining tyrannical power, but Cackletta and Fawful have a surprisingly warm relationship. Fawful trudges the entire length of the kingdom to find Cackletta a new body after her first defeat, and refuses to abandon her until he's knocked out of commission himself. For her part, Cackletta treats Fawful as an equal, recognizing his unique talents as an unconventional example of The Dragon.
- After gaining the Super Hammer and Ultra Hammer, it's possible to take part in a luck-based minigame at the cost of 200 and 500 coins respectively, which allows to get the scrolls for Mario's Bros. Attack Swing Bros. and Luigi's Bros. Attack Cyclone Bros. If Mario is the one to destroy the right rock and get the scroll, Luigi is surprised and cheers. If the scroll is found by Luigi, Mario gives him an applause.
- As soon Mario, Luigi, and Princess Peach make it into Little Fungitown for the first time, they are greet by two nervous Toads that are in awe by their presence. Even one of the Toads recognizes Luigi saying that they don't deserve the honor of meeting him. Luigi's response to this is to blush with embarrassment. It's really good to show in the game where people either don't know Luigi or pretend to know him, it's nice that there are actual people that not only know who Luigi is, but show him as much respect as Mario.
- In the ending, during the flight back home, there's a moment where Luigi talks with Mario, Peach and Toadsworth and cracks a joke, causing all of them to laugh non-stop. It's always nice to see them having a moment of lightheartedness when there's no danger, and it also shows that Mario and Peach like being in Luigi's company and spending time with him.
