12Antz (1998) and A Bug's Life (1998)
Both have: A misfit ant within an oppressed and unimaginative colony, who ultimately finds both romance and wider acceptance as he allies with other bug species and saves that colony from threats within and without. The movie helped a young animation studio establish itself.
But: A Bug's Life's Flik is the kind of open-minded dreamer that you've seen in many kid's movies, whereas Antz's Z (whose name gives the movie its odd spelling) is Woody Allen doing his usual neurotic routine, a coward who struggles to be brave.
Which is worth remembering? Antz. While still offering a satisfying happy ending, Antz portrays a totalitarian society that maps a lot more closely to actual ant behavior than the benign working-joe vision of A Bug's Life. Allen is a genuinely unlikely hero instead of the typical hero-who-just-has-to-realize-he's-a-hero that A Bug's Life has. Antz is just a more distinct movie, whereas much of A Bug's Life now feels like a rough draft of later, better Pixar films.
11Deep Impact (1998) and Armageddon (1998)
Both have: A giant space object that threatens to destroy all life on Earth, unless a team of astronauts can blow it the hell up in time, which involves some of them making the ultimate sacrifice.
But: Deep Impact has far more scientific accuracy (and uses actual astronaut characters), a megatsunami caused by one "deep impact" and some engrossing evacuation politics. Armageddon has a bunch of miners who are given the job instead of astronauts and has an all-or-nothing story: life on Earth will be completely safe or totally destroyed.
Which is worth remembering? Armageddon. Yes, it's dumber, but it's also a lot more fun, the dialogue is much sharper, and it's hard to imagine a more Bruce Willis role than a working-class guy who gets to save the world, or a more Michael Bay movie than one where one gigantic explosion is what's needed to save the day.
10The Truman Show (1998) and EDtv (1999)
Both have: A scripted story satirizing product-placement-funded reality TV, with huge crowds gobbling up video of one fairly ordinary but goofy dude's life (played by an actor trying to transition from comedy to drama). He finally escapes the program, ruining its shareholder value, because all human beings have a right to privacy.
But: Ed of EDtv is aware that he's on television from the first scene and uses that savvy to put pressure on his producers to end his contract, whereas Truman ("true man," get it?) gradually wakes up to that "reality" and rebels against it in more drastic ways.
Which is worth remembering? The Truman Show. No film, except maybe Eternal Sunshine of the Spotless Mind, puts the full range of Jim Carrey's talents on better display, and his attempts to escape the set are more upsetting and therefore, in the end, more rewarding.
9Remember the Titans (2000) and Clash of the Titans (2010/1981)
Both have: A title with the word "Titans" in it, and some clashing that people may need to be told to remember.
But: One is a Denzel Washington biopic about Herman Boone and the racism he faced coaching the desegregated high school football team the Titans, as well as several of the players. In either version of Clash of the Titans, Perseus (one son of Zeus) kills the Medusa and the Kraken. See also the sequel to the remake, Wrath of the Titans, in which Perseus has to save his father from the race of Titans that spawned the gods.
Which is worth remembering? They're clearly apples and oranges, but Remember has a story worth learning and some actual acting, whereas Clash is a pretty loose retelling of myths you could better learn from a children's storybook, and Wrath is a shameless sequel-grab.
828 Days (2000) and 28 Days Later (2002)
Both have: "28 Days" in the title and a disease that makes people into monsters, doing things a healthy person would never consider.
More importantly: The proximity of the release dates and the word "Later" in the title might lead one to believe Later is a sequel. That would be a rather unfortunate misunderstanding.
But: One is a rom-com about a period of time spent in rehab and the challenge of remaining sober afterward. The other is the film that brought zombie horror back into fashion, picking up four weeks after a highly contagious rage-inducing virus has spread through Great Britain, reducing some people to mindless killing machines and unleashing the predator in others.
Which is worth remembering? This is even more of an apples-versus-oranges choice, but 28 Days is a pretty shallow take on a difficult subject that deserves better, whereas 28 Days Later is a favorite among zombie fans.