Martin as a Jerkass Woobie. Think about it: the kid comes out of the cryogenic coma he was in, only to find out his parents have replaced him with a Robot Kid. Jerk Ass tendencies may well be justified there.
Also, most kids push technology, computers, video games, etc to their limits trying to find loopholes and ways to manipulate the programming.
Likewise the crowd at the Flesh Fair revolt when Brendan Gleeson's character wants to destroy David, a robot who looks like a realistic human boy, but they didn't once feel remorse for the non-cute and far less human looking robots. Is Brendan Gleeson correct when he says that David is another Robot and fair game for the fair regardless of how human he looks? Are the crowds awakened to the monstrosity of their appetites when they revolt to save David?
An intentional example for David: is his childlish innocence an genuine act of free will or is he innocent simply because he is programmed to be that way?
Broken Base: Among fans of the film, there is a disagreement whether the time-skip ending improves the film or weakens it.
Common Knowledge: If you've heard the complaints about the movie's ending, you've likely heard them centered around the sheer stupidity of "aliens showing up to fix everything at the last minute". Actually, the creatures in the final scene are never said to be aliens, and Word of God has repeatedly stated that they're just the highly evolved descendants of the mecha.
Ending Fatigue: Some believe that the movie should have ended with David continuously wishing to be a real boy to the carnival Blue Fairy underwater (and still others feel it should have ended with David committing suicide)... but it kept going... and going. In either case the ending fits the general picaresque narrative structure of the film (which Kubrick insisted on, describing the constant changes and movements from the original Pinocchio novel). Likewise it served as Book Ends to the opening Time Skip (20 months between the board meeting and the Swintons adopting David, 2000 years After the End).
"Funny Aneurysm" Moment: Scenes of frozen, distant-future New York City include the twin towers of the World Trade Center poking out of the ice. Spielberg made a conscious decision to leave them in, knowing he would take flak for it either way. Cinemas though (including outside America - the UK was affected) did have signs put up making them aware that footage of the towers featured in case of accidental offence.
Turned on its head here, as most of the humanlike robots are played by live actors - but used to very good effect with CGI-enhanced, partially-broken androids, and many scenes where David just doesn't... seem... quite... human. Like the one where he "breaks" after eating human food.
The main character's actions can be very unnerving sometimes, which gives a subtle indication that in spite of his emotions and fleshy exterior, he is still a machine. The thrown away, out-dated robots that are seen rummaging through a pile of leftover robotic parts in the forest also qualify, but most definitely the "nanny" robot, who happens to be missing 3/4s of her head.
Jude Law's face was sprayed with latex, and his hairline was painted to make it look like a seam, thus make him bizarrely too-perfect to look real.
Villain Has a Point: Something that seems to have been left deliberately ambiguous with Brendon Gleeson's character, the Ringmaster at the Flesh Fair. Sure, he combines all of the most despicable qualities of a revival-tent faith-healing huckster, an Amoral Attorney, and a barker at a house of ill repute; and the audience ultimately denounces him as a monster while showering him with projectiles. However, a question raised by his little speech warning his audience not to let the exceptional artistry by which David was crafted fool them into mistaking him for a real boy continues to linger: what if he's right? Even if one can still make a case that pandering to one's baser instincts (blood-lust, sadism, and vandalism) by trashing robots is an utterly despicable occupation, doesn't his claim that David is just another robot replacement for real humans and that such replacements degrade humanity ("God's children") stand up pretty well to philosophical scrutiny, especially in view of what the story indicates ultimately happened to humanity?
The film was viewed as good, but not as highly received as Kubrick's previous films, with some of the blame being given to Spielberg's "meddling". However, that response has softened since and the film has been received along with Kubrick's others as a masterpiece, a pattern that been carried with almost all of his filmography.
Notably, Roger Ebert initially gave it a score of 3 stars out of 4, and criticized the ending, but since included it in his "Great Movies" list.
Also, what might have helped was the revelation that Kubrick was largely responsible for the film's ending, and Spielberg did his best to incorporate it. Truth be told, it really was an ambitious project between two very different directors, as well as a heartwarming sendoff from one friend to another.
The Woobie: Oh, come on. Who didn't want to reach through the screen and give poor little David a hug?