Our collective response to climate change

Fostering societal systems of greed and competition rather than of cooperation and compassion.

1. We mine and manufacture nutrient dense fertilizer at massive environmental cost.
2. We use the nutrients to grow plants
3. We eat the nutrients in our food
4. We expel 95% of these nutrients in our waste
5. We dump our waste into the rivers and oceans with all the nutrients (often we purposefully destroy the nitrogen in the waste since it causes so much damage to rivers and oceans)
6. We need new nutrients to grow plants

Before humans there was a nutrient cycle. Now it's just a pipe from mining to the ocean that passes through us. The ecological cost of this is immeasurable, but we don't notice because fertilizer helps us feed starving people and waste management is important to avoid disease.

We need to close the loop again!

Having the intelligence to create technology but not enough intelligence to understand the implications.

letting unqualified businessmen rule the planet instead of experts in their given fields.

Every time someone tried to make "a weapon so powerful it would make people not want to wage war".

Several weapons are on this list, from the cannon to the machine gun to, most famously, the atomic bomb.

The fact that this happened once would've been understandable. The fact this escalated to nuclear weapons because people just tried pushing this idea is nuts though.

This is not toward so much the technology, with all tech being no less inevitable, but more to do with the intentions/hindsight/foresight of the people making something that can only be produced by an assembly in a seemingly dire setting, as opposed to something like AI, which does not stem from that and which would've come around at some time.

By extension, this extends to populism in general, a mindset that from experience I refuse to compliment. I'm surrounded by people every day who come off as thinking with their feet and not with the methodological part of them, and my experiences with this have never allowed me to be fully at peace.

Opting for gasoline over electricity early on when cars started to become a thing, we were already going electric, but a smear campaign put fear into people's minds about electric and switched tk gasoline.

Leaded fuel

Investing everything in engines and abandoning battery development in the early 1900s. Lead-acid batteries were heavy but usable, and electric cars were more popular until electric starters were added to engines. A disproportionately big, short-lived reason was the lack of sufficient electrical grid for electric cars trying to go far.

Nobody in government was thinking ahead, so everyone was forced to trying to make their own money NOW, and that's how we get inhumane tech in general. Same thing happening in computers for decades now. We need centralised R&D free from market influence for the benefit of all life.

“Let’s just divide up Poland and keep the peace. We can focus our whole energy on the western front, you can save yourselves bloodshed by the tanker load, and in a few short years we can share dominion over a subjugated world.”

“You so right, that sounds like a great plan”

“Hey guess what I just decided”

The whole world would have been different. It was still a pretty close thing with help from the Soviets and with Germany fighting a ludicrous two-front war for literally no military or geopolitical reason at all.

Many of us will be miserable for the rest of our lives and society won't care.

Humans.

Human history, as a whole, is so depressing and meandering it's a weird question to try and answer. Were the great empires a success, or a failure? It depends on if you're measuring monuments built or social justice enacted, and if you're comparing against modern polities or whatever shitty local warlord they replaced. History doesn't really have an end goal, as much as we'd like it to.

Maybe you just meant a personal failure:

Thomas Midgley is one of my favourites, because he's famous for three things: Inventing leaded gasoline, inventing ozone-destroying PCBs, and inventing an accessibility contraption that strangled Thomas Midgley. He did nothing else of note; he's like the real life Bloody Stupid Johnson.

Pheidippides of Battle of Marathon fame is famous for running a long way just to deliver some news first, and then dying from exhaustion. ~~People regularly make the same trip and are fine.~~ He was regarded as a hero, and the races were originally in his honour, but I wouldn't want to be him. Edit: Maybe not a great example, actually. The story names a much longer distance than a marathon, although it's kinda mythical.

Muhammad II of Khwarazm received an envoy from Ghengis Khan, who wasn't bent on invading at all but wanted trade, and decided to steal their shit and kick them out instead. Then he killed the people sent next to ask for a nice apology. You can guess where that went.

The Soviets once tried to sextort Indonesian quasi-communist leader Sukarno with a tape. It did not work, because he was shamelessly proud of his "virility". In at least some tellings he misinterprets the KGB's presentation as a gift, although I doubt he could have been that dumb.

Let's go with the atomic bomb...if you disagree, consider that we made a weapon too powerful to ever be used again, but nations that have them get taken way more seriously in diplomacy.

And let's be serious, it's pretty much tick-tock, tick-tock before they get used again when they get put in the hands of zealots. Let's be doubly serious, it will be religion that convinces some leader that they are within their divine rights to cleanse the world of their enemies.

Ego.

The election of Richard Nixon. I sincerely believe that's where we traded the "flying cars robot butlers" timeline for the "worst inequality of literally ever" timeline.

MS Excel

Money

When people started taking dudes in fancy hats seriously

Agriculture.