Muriel being all too sweet and motherly to the Scooby Gang. When Velma chides herself for not solving one of Muriel's many riddles, Muriel tells her she's already smarter than the riddles, which does cheer her up. When Shaggy gets scared by the giant cicada on his back and is freaking out, she calmly tells him to sit down and watch some television.
On that note, Mystery Inc's treatment of Muriel. The entire group is protective of her and treats her with the utmost care, and you can see plenty of sweet little moments where they're helping Muriel keep up with them or including her in the conversation whenever possible. In just one movie, it's like if Muriel became the group's honorary grandma.
Just how well Shaggy, Scooby and Courage all get along with each other. Especially the scene where Shaggy tells Courage that courage isn't the absence of fear, it's the ability to face it, which allows him to face the Cicada Queen. Even more impactful considering Courage's limited amount of friends in the show. And considering his traumatic backstory, it must be nice to have another dog to befriend.
Small stuff, but every time Courage jumps between Muriel's arms as she catches him with a hug, even happily wagging his little tail at one point.
