My best memory of the trip was in Paris, before the attacks. Our group of six friends went to my cousin's little apartment and shared a delicious home-cooked meal with my cousins, their spouses, and my aunt and uncle. There wasn't a single language we shared between us. I thought of making a Venn diagram of who spoke what, but it made my head explode. Everybody spoke at least two languages, but nobody spoke the same two. There was English, French, Mandarin, Cantonese, Spanish, and I think someone pulled out a little German? Every time you turned to talk to someone else, you switched languages, sometimes having to find a third person to bridge the gap. But it never felt like a barrier; it felt like a wonderful game among good friends, even though most of these people had just met. I still smile looking back at it.

Anyway, I like to think that is how things could have turned out if we'd gone a different way.

Sometimes, the choice to live also required heroism, as in the case of Lauren Manning, who escaped the building on fire and ran across the street to put herself out on the grass. As she lay there with 82 percent of her body burned, she felt an "overwhelming ... impulse to let go." Unable to stand the thought of leaving her 10-month-old son behind, she fought to stay alive that day, and through months of painful recovery, until she could come home to him.

The site was also flooded with volunteers of all kinds putting in extreme hours to search the rubble and support those searching the rubble. People from all over the country donated money (an estimated $1.2 billion) and more blood than the Red Cross could use. I like to imagine that they put the rest in a giant tank and sprayed it out of a fire hose on the set of a Tarantino film.

You might have heard of the asshole Starbucks location which took advantage of the attacks to charge exorbitant prices for bottled water. But the reason it became such a viral story was that it was so rare and contrasted so sharply with what everybody else was doing. Even other nearby Starbucks locations were serving free water and coffee to rescue workers, so I guess whoever was running this one was just a champion sociopath.

In the years since, I've barely heard any tales of these financial managers and office workers. And while I do hear people talk a lot about the cops and firefighters and rescue workers, they seem to revere them only as abstractions and symbols, often using them as a badge of how patriotic they are, or how unpatriotic the person they are arguing with is. When it comes time to (literally) put our money where our mouth is, our gratitude level seems pretty sad, as getting money for these people's health problems has been like pulling teeth. From a shark.

In the days after 9/11 some comedians said this was totally going to change the face of humor. Time's Roger Rosenblatt wrote a piece called "The Age of Irony Comes To An End" -- which, ironically, people started mocking him for like maybe hours after.

Today, this seems laughably naive, and we think of it as the dismissable ravings of people too stunned to think straight, like a drunk telling everybody at the bar how he really, no, REALLY loves them. Boy, it sure would have been dumb, we think, to have made any permanent vows at that time to turn the future landscape of humor into nothing but PG-rated puns and corny dad jokes. Good thing we got over that fast!

What we forget is that almost everybody goes a little overboard when they first stumble on some epiphany, like quitting alcohol or smoking, or discovering that other groups experience racism or sexism, or joining CrossFit. They kind of go full zealot for a bit, but most people quickly settle down to a sustainable level. It would be a mistake if, out of embarrassment over the initial wave of zealotry, the person put the whole experience away in their closet of shame and went back to the way they were -- back to addiction, or ignoring racism, or a non-cult-like exercise regimen.

We focused on how dumb it was to talk about always making positive jokes all the time, and missed an opportunity to think about the different kinds of negative jokes we make, and whether all of them are really worth keeping. I'm not talking about "censoring" other people's jokes; I'm talking about each individual thinking about the kind of jokes they want to make themselves. How much humor do we lose by not saying "fag," or other slurs, and might it be worth it? Is it worth publicly making fun of some hobbyist's badly-written personal blog in my column if it's going to direct a bunch of trolls to her comment section to harass and insult her? Does it depend on how funny her terrible blog is, or does that not matter? Is it worth it to make a joke that makes a million people laugh, only to be forgotten about a few minutes later, at the expense of causing a hundred people piercing hurt that lasts for months?

I feel like we're gradually coming around to asking these questions now, but we had a shot to pick up on this 15 years ago, and it could have spared so much meaningless meanness and so much wasted time crafting forgotten jokes that even their makers cringe at and try to distance themselves from now. Time that could have been better spent making good jokes, or maybe gardening or playing video games or something.

In the immediate aftermath, we didn't suddenly agree about how we should keep the country safe, but we did believe, even for a brief moment, that the different people around us wanted the country to be safe. Strangers would hug strangers.

We knew were on the same team. We disagreed on strategy, but we knew this other person, wrongheaded as they may have been, was sickened just like us by the death toll, by the happy families torn apart in one horrible instant.

But not a lot of time passed before large swaths of Americans were perfectly willing to say that President Bush (and thousands of necessary collaborators) allowed or even planned 9/11. We now have a presidential candidate saying that "thousands" of American citizens with a different religion than him were cheering as they saw the towers come down (untrue, of course), or that our current president welcomes terrorist attacks or founded a terrorist organization, and millions of supporters are going, "Sure, that makes sense."

It's become so common to casually talk about regular people who disagree with us as if they are a different species that just wakes up plotting evil, to the point where we can't even accept anything human they do (like hanging out with their kids) without explaining it away as a PR stunt or saying they must really be beating their kids behind the scenes. You can say someone is wrong and fight tooth and nail against their dangerous ideas without saying they're incapable of all love and they would gleefully blow up a school.

We spend our public lives putting on the face we think will impress people the most -- the coolest, smartest, wittiest, most authoritative, not-mad-bro, put-together face. Ironically, it is when a crisis temporarily shatters this mask and reveals the vulnerability and hurt underneath that some of our worst enemies suddenly realize we are humans too. And we in turn see that our evil nemesis can also feel sad and scared. And then we hurriedly patch up the masks and agree to never speak of this again and go back at it harder than ever.

I'm not saying we should all hold hands and sing Kumbaya. All I'm saying is that we should at least acknowledge the majority of people on the other side of an issue wouldn't welcome the murder of thousands of innocent people.

Meanwhile, the ugly emotions -- fear and hate -- are like weeds. Not only will they survive without interference, they will thrive and dominate. You might be surprised to hear that two months after 9/11, the percentage of Americans who had a favorable view of Muslim Americans had actually increased from before the attacks, from 45 percent to 59 percent, thanks in part to some words from President Bush, of all people. This dropped steadily to 35 percent in 2010 and 27 percent by 2014. Suspicion and distrust not only stick around just fine for 15 years, but grow big and strong with regular feedings.

Starved and neglected, the good impulses -- love, bravery, fellowship, compassion, sacrifice -- withered. The bad impulses ran wild. We watched patriotism corrupted into shallow jingoism, the desire for justice into bloodthirsty belligerence, and watchful vigilance mutated into hateful paranoia. Genuine stories of heroism were turned into propaganda. Real grief was used to push emotional buttons and manipulate voters into war and surrendering civil liberties. We became so familiar with the corrupted forms that we considered the purer originals merely phony euphemisms for them.

Those of us repelled by the self-serving distortion of the 9/11 memory gave in to cynicism and hopelessness. We remembered it as the moment that drove people to be trigger-happy for war, to trade freedom for a false promise of safety, and to treat millions of fellow citizens like secret terrorists. We forgot it had also moved us to make our own hopeful promises. We swore we were going to volunteer more, or change the way we treated people, or quit playing Counter-Strike all day and take concrete steps to pursue our dream of being a game dev or a writer or a television chef. I stuck to my guns and became Mario Batali, but how many of the rest of us followed through?

We remember how post-9/11 emotions made a lot of people shittier. We forgot how they had made us want to be good.

I know 9/11 wasn't necessarily a moment of clarity for everybody. But most of us have some moment, public or personal, which made everything dumb seem unimportant and everything worthy grow big. And most of us expected that moment to automatically change our lives, and didn't bother to make it change us. So we lost it as quickly as it came. That's why I latched onto "Never Forget." It's something you have to do deliberately, purposefully. It's not "Yeah, I'm sure I'll never forget."

I don't have that sticker anymore, or the car. My church did a thing a few years ago where they gave cars to people who needed them, so I donated it. Mine went to a single mom who lost her last car because her abusive ex smashed the door in. I don't remember if the sticker was still on the car when we gave it to her, but I think the thing that made me put the sticker on the car would have been happy.

Christina can be found on Twitter or Facebook.

Learn how effective terrorism actually is in The 6 Weirdest Things We've Learned Since 9/11, and get inside the mindset of a 9/11 conspiracy theorist in I Was A Professional 9/11 Truther (And I Gave It Up).

Subscribe to our YouTube channel to hear the unfiltered truth about cars in If Car Commercials Were Honest, and watch other videos you won't see on the site!

Also follow us on Facebook, because summer is almost over, which means it's time to stay indoors and read Cracked!