Jennifer: “Watchmen,” the series on HBO that just completed its run in December 2019, is a hard look at American history — and mythology. It captures, breathtakingly, the profound and unhealable racism written into this country’s DNA; it also shows that a woman of color can be a force for justice — and in so doing, it reinvents what we think of when we use the word “superhero.”

What’s something or someone you think changed the course of history for the better, perhaps in ways that are only beginning to be appreciated?

Farhad: Batteries! I think we’re going to get lots of better technologies, especially better transportation tech, thanks to better batteries. Batteries haven’t been getting better at the rate of microprocessors, but we have seen incremental improvements in capacity and cost over the decade, and those improvements will give us lots of more-efficient and safer ways to move around cities.

Margaret: Fake meat isn’t going to turn everyone into a vegan, and it won’t cut down on meat consumption overnight, but it might create a middle way that omnivores find appealing — perhaps even appealing enough to slow the rate at which forests are converted into pastures for livestock. In time it might even mean that pastures are allowed to become forests again.

Bari: The Hong Kong protesters are, literally and figuratively, picking up the flag we have put down. They are at the front lines of the fight for liberty against a Chinese regime that is using technology that promised to make us more free to make human beings more unfree than ever before. They will be remembered not just as heroic, but as prophetic.

Jennifer: Sarah Kate Ellis became the C.E.O. of the L.G.B.T.Q. media advocacy nonprofit Glaad in 2014. At that time, Glaad was teetering on insolvency and irrelevancy. (I know, because I was on its board of directors at the time.) In short order, Ms. Ellis saved that organization and placed it at the forefront of the civil rights movement for queer people. You can’t underestimate the impact of Glaad: So many straight and cis people form their opinions about L.G.B.T.Q. Americans from television and film and other media. Ms. Ellis has helped change the stories we tell about queer Americans. These were once stories about mere “tolerance”; today they are something more like celebration.

What about something that changed history for the worse? (Besides the 2016 election and the fallout of the 2007-08 financial crisis.)

Farhad: Tribalism fed by social networks. It’s becoming increasingly difficult to understand people who aren’t in your circle; we are actively divorcing ourselves from people who don’t share our experiences. This will end badly.

Margaret: I agree with Farhad. Social media has made it too easy to forget that people are more than their political opinions. Engaging with our fellow human beings on many levels, and not just a political level, is our only hope for finding enough common ground to move together toward something better. And right now we’re in desperate need of something better.