Sorry for the question, but where are you from? I learned this with my mother, so I don’t know if it’s something common here (Brazil) or something that she picked from her Polish or Italian relatives.

That’s surprisingly accurate, as people here are highlighting (it makes geometrical sense when dealing with complex numbers).

My nephew once asked me this question. The way that I explained it was like this:

• the friend of my friend is my friend; (+1)*(+1) = (+1)
• the enemy of my friend is my enemy; (+1)*(-1) = (-1)
• the friend of my enemy is my enemy; (-1)*(+1) = (-1)
• the enemy of my enemy is my friend; (-1)*(-1) = (+1)

It’s a different analogy but it makes intuitive sense, even for kids. And it works nice as mnemonic too.

Stating obvious shit like it was some hidden piece of wisdom? Inability to handle subtleties like “lying” vs. “saying an incorrect statement”? Voting system? People repeating the same shit over and over, without reading the others’ comments?

EDIT: I’m highlighting that this YT comment section shows a lot of things to hate in Reddit. In some aspects they’re behaving exactly like redditors; in some they’re actually doing it better, even if YT is a cesspool of idiocy.

Calcium chloride exists, it’s CaCl₂. You need two chloride anions for each calcium cation. [see note*]

It’s safe to eat as long as food grade. In fact it’s used in cheesemaking. It’s salty and bitter. It’s also used to dehydrate stuff in laboratory, since it absorbs water like there’s no tomorrow.

It doesn’t behave like metallic calcium at all. Just like sodium chloride (aka table salt) doesn’t behave like metallic sodium (warning: loud noise).

*Note: technically CaCl (one chlorine) exists, as a diatomic molecule. Rarely found in stars, you won’t find it in Earth.

Don’t feel discouraged by the Karen above, that should’ve stayed in Reddit alongside their peers. Thoughtful contribution is often verbose, and there’s nothing wrong with it.

Lunix sucks so much that it got stuck into the version 2 for years.

No, but simply looking for something and then remembering that it doesn’t exist makes me feel stupid.

It’s the Sex update! They actually released it! The mad devs!

Dunno in Brazil as a whole but at least in my city, school uniforms are default. They’re simply taken for granted, not a “conservative vs. liberal” matter. Each school picks its own, but it usually boils down to a shirt, baggy pants, and a jacket (most schools cut you some slack on really cold days to swap it with a warmer one).

Glacial = anhydrous. People call it this way because pure acetic acid has a rather high freezing point (16°C), and it looks a lot like plain ice when frozen. (It still stinks vinegar once you open the bottle though.) But once you add even a bit of water, the freezing point drops considerably, so acetic acid solutions don’t show the same “ice”.

So in colder days, you need to rewarm it back into a liquid. Then people get really sloppy (I know it not just from that professor’s anecdote, but from watching it). They say “I’m just rewarming it, and it’s just acetic acid, what could go wrong?”. Well, it’s still a big flask of a corrosive, volatile, and flammable substance.

In the meantime, the same people doing dangerous reactions like nitration (it literally explodes if you let it get too hot - spreading nitric acid, sulphuric acid, and some carcinogenic solvent) “miraculously” pay full attention, obsessively taking care of the temperature of the ice bath.

Part of the advice that I mentioned in that comment chain is that - smaller dangers are still dangers, do not underestimate them.

Long story short: someone else’s advice ITT reminded me a uni professor talking about a student hurting themself with glacial acetic acid. That reminded me how often I’m using alcohol vinegar for cleaning (alcohol vinegar is basically one part of glacial acetic acid for 24 parts of water), but I don’t see people doing it often - instead they often buy expensive cleaning agents that they use everywhere as “magical” solutions.

Most “rules of thumb” become awful advice when used indiscriminately.

People assign slightly different meanings to the same words. You need to acknowledge this to understand what they say.

Words also change meaning depending on the context.

When you still don’t get what someone else said, it’s often more useful to think that you’re lacking a key piece of info than to assume that the other person does.

Hell is paved with good intentions. This piece of advice is popular, but still not heard enough.

Related to the above: if someone in your life is consistently rushing towards conclusions, based on little to no information, minimise the impact of that person in your life.

Have at least one recipe using leftovers of other recipes. It’ll reduce waste.

Alcohol vinegar is bland, boring, and awful for cooking. But it’s a great cleaning agent.

Identify what you need to keep vs. throw away. Don’t “default” this indiscriminately, analyse it on a per case basis.

The world does not revolve around your belly button and nature won’t “magically” change because of your feelings.

You can cultivate herbs in a backyard. No backyard? Flower pots. No flower pots? Old margarine pot. (Check which herbs grow well where you live.)

It’s Latin and it says we must all die

There’s no “must”: it states for a fact that you’re to die, not that you should/need/must.

A rough translation would be “remember that you’ll die”, or “remember that you are to die” (keeping the infinitive). Or even “remember death”, it’s close enough in spirit.

fons: egomet, latine loquor.

I usually twist this into “memento mori, quoque uiuere” (remember [that you’ll] die, also [that you’ll] live).

Like, not trying to become worm food full of regrets is nice and dandy, but remember that you’ll suffer the consequences of a few of your actions while you’re still alive.

Another from chemistry: “small dangers are still dangers, don’t underestimate them”.

This was in my first uni. The person saying that mentioned how he never saw students harming themselves with cyanide, nitration solutions (sulphuric+nitric - highly corrosive and explosive) or the likes. No, it was always with dumb shit like glacial acetic acid skin burns, or a solvent catching fire.

Not common in general usage nowadays. Perhaps it avoided the shift?

PEBKAC

Every time that I see this acronym I’m tempted to pronounce it as ['rʲefkas], then I remember “ah, it isn’t Cyrillic”.

Isn’t lol short for “laughing out loud”?

Wiktionary lists both “laughing out loud” and “lots of laughs”. Nowadays though it’s neither; on a pragmatic level it doesn’t convey “I’m laughing” / “I laughed”, it conveys amusement and/or lack of seriousness, depending on the context.

• [Alice] The Sun is a star.
• [Bob] yeah sure the sun only appears at night lol (implying: “I’m amused at what Alice said, and I don’t take it seriously.”)

I don’t even recall pronouncing it in loud voice. In English I simply say “what you see is what you get”, and in Portuguese or Italian I rephrase it. (Although I remember at least one person calling it ['vizi 'vige] in Portuguese. And I was, like… “what?”)

What else is it supposed to be?

• fear the whales - because sharks are not enough.
• ferry the warriors - how else will they reach Hades?
• fuck the West - yes, I had to politicise this.
• feed the woodpeckers - hipster version of granny throwing popcorn to the pigeons.
• feel the wetness - this is sounding like porn already.