These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
The Lipshitz muscial number that's only in the TV Broadcasts could count as well.
Critical Dissonance: The movie received mixed reviews from critics, but opened at #1 at the box office, and became the first animated movie not made by Disney to gross over $100 million in the United States. Course it helped that the series was very popular at that point.
Design Student's Orgasm: Well it is a Klasky-Csupo production. Of particular note is the scene of the traditionally animated Stu flying his computer generated whirligig invention through a photographed sky!
Moral Event Horizon: Tommy comes dangerously close to crossing this line when he gets so fed up with his brother, after having left his friends behind for Dil's sake, that he nearly pours banana baby food on him to let him be devoured by the monkeys
Could possibly also count as Despair Event Horizon because Tommy did have more than enough reason to be upset by that point.
Tear Jerker: Early on after Dil arrives you see Tommy having to sing to himself because his parents are too busy, and then it goes to Spike, howling in the rain.
The scene in the rain where Tommy finally snaps and considers leaving Dil behind in the forest with the monkeys. Probably the most dramatic scene in the history of the series, and quite impressive when you consider that this is a one year old and his newborn brother, and yet it can still send shivers down anyone's spine and tears down their faces.
Even more impressive is he's planning on pouring banana-flavored baby food on Dil and leaving him with monkeys, and it somehow manages to make you cry instead of laugh at how how ridiculous it all is.
When Tommy is about to ask the "Lizard" (Actually Tommy's father) to send them back home, he looks back at the other babies, who are all crying over Spike's sacrifice, and instead wishes for his doggy back.