What red flag could be a green flag in the right context?

Everything!

Say "I love you babe!"

Long term relationship - green
First date - red

Say "I'll beat you!"

Racing a kid - green
When stoping in the middle of the woods with your date - red

Let a fart rip

With a friend when the room is silent - green
On your date when she rims you - red

I can go on

A literal flag colored red, if you or the flag is moving towards the other so fast as to blueshift it to green.

Sooooo, wavelengths (λ) become longer when something moves away (redshift) and become shorter when something moves towards you (blueshift).

For a red flag (λ0=610nm) to become a green flag (λ1=549nm), it has to move towards you quite fast. But how fast is 'quite fast'?

Using the formula

flag_velocity / speed of light (c) = difference in wavelengths / starting wavelength

we get

flag_velocity = (610-549) / 610 * c = 61 / 610 * c = 1/10 * c

This means: the flag has to move with about c/10 = 30 000 000 m/s = 108 000 000 km/h = 67 108 100 mph. Yeah, that's quite fast.

(Disclaimer:

use info on own risk

values for λ were chosen in a way to make calculations easy. There is no info on what shade of red or green the flag is. The final result will be about the same.

With speeds at around 10% of c, I should use the formula considering the relativistic doppler effect... However, i wont. Thanks.)
- So you're saying I should date her right?
- Well, they certainly did the math

Red flag: My friend once saw what looked like people setting a RadioShack ablaze and stealing all the expensive electronics and making off with them all.

Green flag context: It was actually a faulty electronic that caused the fire, and the "thieves" were Good Samaritans saving everything from getting burned.

Hope they got all of the free battery of the month cards!
- What are those?
Witnessing a crime is a red flag?
- The crime itself is the red flag, or would've been if it was truly a crime.

If a person with protanopia/deuteranopia looks at a red flag, one sees green-ish flag.

Hi, protan here, you are not a correct. I am red-blind and it's more like reds are extremely muted, with weaker reds looking kinda grey.

Yellows turn into greens, though, for perhaps predictable reasons.

Red flags: wants constant attention, nags constantly for me to make her dinner, sometimes physically hurts me.

Green flag: when it's my cat.

Or a toddler/infant.

Of ur moving fast enough the doppler effect.

Did you consciously try to make yourself look as dumb as possible?
- They're just not moving fast enough, or possibly in the right direction.
- Just checked ur comment history and i think ur a little insecure about ur intelegence. Dont worry ill let u have the last word.

Lying and pretending to know something who's actually a complete stranger to them

When the stranger is a drunk woman in distress clearly trying to get away from a predator.

If you’re colorblind.

Color blindness test

If your partner is indiscriminately murdering vaguely shady people with a bow and arrow it will probably be fine, cause he’ll reset the universe and become god (or something?) just be sure to weep about being betrayed at least once every seas—er… year.

JoJo?
- ArRow

Partners who want to do everything for you.

They're very giving, and will do you so many favors, and cater to your whims. Favorite ice cream? Let me go buy it for you! Need something from the store? I'll go get it! Need a ride? Got you covered!

Once they have you "locked down" (married, pregnant, in a long-term lease, dependant on them for transport, etc.) they can do a 180 and suddenly "you owe them". No more favors. Only guilt. They'll isolate you and make every negative emotion they feel be "your fault."

They want you to become dependant on them so they can use and manipulate you.

Be so very careful with overly kind/giving people. Never let yourself be 100% dependant on someone else. Ever. No matter how nice they are to you.

I think you misread the question.
- Oh, I totally did. Whoops. I'm tired. Keepin' it up.

Piss-play fetish if you swim around the Great Barrier Reef a lot.

I'm sorry, what?
- GBR has crazy jellyfish. Otherwise: https://www.youtube.com/watch?v=DswPLKfi00A

Multiple Personalities.

When you say you wanna see other people, they already are other people!

Eating in an extremely unhealthy way if you're an actor and it's necessary to gain weight for a movie, or it's for an official science experiment.

Sometimes a bad credit rating is a good thing

USSR when you want to liberate the working class (or if you have red-green color blindness)

Or when you're looking for the Chinese consulate.

Zhongshan Island

The 2021 Belgian Grand Prix

Context?
- The race was planned to run for 44 laps, but ended during the third lap due to wet conditions. Laps one and two took place behind the safety car before a red flag stopped the race on lap three. The sporting regulations required the results be taken from the end of lap one, with half points given to drivers who finished in the top 10 positions as less than 75% of the originally scheduled race distance had been completed.
  
  https://en.wikipedia.org/wiki/2021_Belgian_Grand_Prix

Hating the democratic party of the United States. Without any other context you would assume they are a republican. But once they start critiquing marx and explaning how Trotsky's permanent revolution is the only viable path forward you know they are good people.

Alternatively, if someone supports the dems no matter what, that is a red flag that should never be overlooked especially when they start rationalizing their perverted beliefs by name-dropping minorities out of the blue.

What
You're not incorrect but this isn't the place lmao
- I'm from lemmy.marxistleninist It's always the correct place to dump on the Liberals.