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.
Animation Age Ghetto: Sort of averted, sort of not. The film was highly successful both financially and critically despite being rated PG. But nowadays, bowdlerized versions of it get aired on TV channels geared toward children.
Complete Monster: General Mandible, a megalomaniac ant soldier who views worker ants as inferior vermin and soldiers as superior. He manipulates the Queen into rejecting peace negotiations with a hostile colony of Termites and sends all the soldiers loyal to her on a suicide mission to attack the Termites and secure his power. Both sides are completely destroyed in the fight except for a single ant named Z, which irritates him to no end. He engineers a new dig for the miners so they will hit a water source that will drown every ant in the colony including the Queen, except for his small faction of army loyalists who will be blindly obedient to him. He tortures Z's best friend Weaver to find Princess Bala after Z took her away, threatens to kill Weaver's girlfriend if he doesn't comply, then orders Z killed seconds after he promised not to do so and arranges Weaver's death as well. To start his new ideal colony he plans to force Princess Bala to marry him after he has killed her mother and everyone else.
A small one but after the whole bar fiasco Z has found someone he actually loves and starts acting much more lively around everyone. And then it becomes sad once again once he goes back to the bar and waits for Princess Bala, once she doesn't come around Z is now the only patron left in the bar. The bartender asks if he wants another aphid beer, to which Z sadly declines and says he's leaving for the night. It's Woody's delivery that really makes it sad.
They Copied It, So It Sucks: John Lasseter felt doublecrossed when he heard about this film being produced, considering he discussed the general idea of A Bug's Life with Jeffery Katzenberg before he left to form Dreamworks. The fact that Katzenberg then offered to stop production if Disney rescheduled the Pixar film away from his major film, The Prince of Egypt, ticked him off more as blackmail.
It should be said though that despite some very few similarities the two films are overall incredibly separate movies. They have Almost Nothing in common.
Too Cool to Live: Barbatus, one of the few few soldiers loyal to the Queen and bites the dust after finally being reduced to a head