There are also those that believe Hal's behavior is symptomatic of some kind of Ambiguous Disorder.
Is Metro-Man a deconstruction of the Superman paragon — who ultimately is willing to sacrifice everything for his own happiness? Or is he a true paragon of faith who knew that Megamind could rise to the challenge and that plunging the city into darkness was necessary for both of their happiness? Also, did he simply realize that since Megamind is a Poke the Poodle sort of villain, that being a superhero against him was pointless?
Angst? What Angst?: By any metric, Megamind had a spectacularly crappy life and upbringing — home planet destroyed, raised in jail, bullied at school, no friends except for Minion — but doesn't seem particularly bothered by most of it.
While Megamind is generally well received, it differs between those who find it to be a hilarious masterpiece while others thinks that, while it is good, it could have been a lot funnier and didn't quite reach its potential. There's also the third sect of people who feel that the comedy is lacking, but that it's made up for by the more dramatic elements.
The spelling of Hal's super"hero" alter ego: Is it "Titan" or "Tighten"? Some prefer "Titan" because it isn't as ridiculous, while others prefer "Tighten", due to the symbolism attached to the character as "Tighten" is the name that Hal unintentionally gave the supervillain he turned himself into.
Cult Classic: After almost a decade, Megamind still hasn't lost its edge.
Designated Hero: Invoked and lampshaded with Metroman. He was a Spoiled Brat as a kid who kept "punishing" Megamind for trying to emulate the cool stuff Mr. Goody Two-Shoes did, to the point of moving the school away literally after Megamind snapped and caused trouble on purpose. Yet he became the hero of the city, with he and Megamind treating their animosity as a game. In the end, he reveals he was suffering a Hollywood Midlife Crisis after realizing he and Megamind were "going through the motions" and decided to fake his death on the spur of the moment. When Roxanne yells at him for being so irresponsible and leaving the city to Megamind's mercy — and Megamind who actually didn't cause any harm agrees with her— Metroman's only response is to refuse to help because he's retired from hero works, and says good will always rise up to stop evil while giving Megamind a meaningful look. It's a valid point in how someone who saves lives may not necessarily be a good person.
Draco in Leather Pants: There are a handful of people who romanticize Hal as a lovable loser who just needed a shot at love. They fail to realize that Hal is a deconstruction of that character type and showed his true nature once he had super-powers, threatening the entire city simply because he got friend-zoned. Some people even say it's not his fault because Roxanne "broke his heart". They forget than Roxanne has the right as a human being to say no to a man if she isn't attracted to him. Hal seems incapable of taking no for an answer when human, and when turned into Titan, he only becomes more entitled.
Ear Worm: ♪ I have eyes. That can see. Right through leeeeeeead. ♪
Foe Yay: Like woah between Megamind and Metro Man: Megamind goes into mourning over Metro Man, bringing flowers to his statue and lamenting about all the battles they'll now never have and how it's "not the same" without him.
Megamind is visibly relieved Metro Man isn't dead when he sees his cape flying from the explosion, a long moment before his "Oh, Crap!, he's alive and coming towards me."
There's also the scene where Roxanne takes Megamind to Metro Man's hideout. He's practically squeeing at all of the stuff and even puts on Metro Man's cape. Roxanne seems uncertain how to take his reaction.
Genius Bonus: If you look carefully during the scene where the death ray is firing at Metro Man, you can tell that Metro City is in Michigan. Before automobiles moved in, copper mining was Michigan's biggest industry. Metro Man's weakness is copper. Weaksauce Weakness indeed (if he hadn't been making that up).
Harsher in Hindsight: Titan goes on a rampage, threatening Metro City and tries to kill Megamind and Roxanne simply because she rejected him. Four years later, the Isla Vista killings happened for similar reasons.
Titan's remarks on how the Easter Bunny and the Tooth Fairy don't exist, in light of Rise of the Guardians, another DreamWorks Animation film. Then again, the studio pretty much pretends that RotG does not exist, so it kind of makes sense.
Hal Stewart having a composite name of two different Green Lanterns, being voiced by Jonah Hill and acting clingy towards a Lois Lane expy became this when The LEGO Movie came out, which had a Green Lantern (most likely Hal Jordan) voiced by Jonah Hill acting clingy towards Lego Superman.
Speaking of The Lego Movie, all of the "artifacts" (such as "the po-leesh remover of na-eel) sound as if Megamind named them. Which he did... from a certain point of view.
It Was His Sled: Titan choosing to become a villain after being rejected by Roxanne. Thanks to the internet, it's no longer a twist anymore.
Jerkass Woobie: Megamind himself before his HeelFace Turn. His villainy is closer to the Poke the Poodle variety, but he still regularly kidnaps someone, threatens them with bodily harm, and (unsuccessfully) tries to kill his nemesis. On the other hand, his planet was destroyed, had a potential family stolen from him by a coincidence, grew up in a prison and was ostracized as a child for (arguably) doing the exact same things Metro Man did.
Bernard. How would you feel if you woke up in a washing machine after God knows how long, only to get immediately knocked out again by a mechanical fish-ape? Poor guy.
Memetic Mutation: "And I love YOU, Random Citizen!" is commonly quoted whenever someone does or says something awesome.
Moral Event Horizon: Titan going on an rampage over Roxanne rejecting him is bad enough, but being willing to kill Megamind and Roxanne crossed this.
Most Wonderful Sound: The opening notes of "Welcome to the Jungle." In-story too: just look at the expression on Roxanne's face.
One-Scene Wonder: The real Bernard appears in two scenes. One has him acting cold towards Roxanne and mocking Megamind's "costume" before being dehydrated, and the other has him rehydrated by Minion and getting whacked by his stick.
Squick: "Come out you little freak! I wanna see what that BIG BRAIN LOOKS LIKE ON THE PAVEMENT!"
They Wasted a Perfectly Good Plot: As Megamind talks to Minion about who they should make into a hero, and how this hero should be "someone of noble heart and mind, who puts the welfare of others above their own", he is interrupted by his mobile ringing. It's Roxanne. She is right outside. Because she tracked him down to stop him. This is more of an oversight on Megamind's part, since he never entertains the idea of turning Roxanne into a heroine to stop him, partially explained by him being in a blind panic to get her out of his lair ASAP.
Vindicated by History: While it received okay-to-middling reception upon release, the advent of dozens of superhero movies in the 2010's caused many to return to Megamind, praising its strong comedic and narrative writing as well as its excellent animation. Compounding this is people taking notice in the Values Resonance in Hal's arc moving into the late 2010s, as sexual harassment, unwanted advances, and men feeling entitled to women came strongly into cultural focus.