Note: VideoGame/MinionQuestTheSearchForBowser examples go [[HeartWarming/MinionQuestTheSearchForBowser here]].
* Every time Mario and Luigi share a hug when they meet after being separated.
* Also deserving of mention is their hugging Princess Peach after she is kidnapped in Teehee Valley (which you can repeat, even multiple times, if [[VideoGameCrueltyPotential 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 GroupHug, which is very touching as it really 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 supporting his unconscious body.