if you didn’t know stuff about humans you would think they get mad at the weirdest stuff
like one human raises their thumb to another human that’s good, humans like that
one human raises their middle finger to another human
humans do NOT LIKE THAT
humans think that is a BAD FINGER
don’t you DARE raise that specific finger at me
any other finger is ok just not that one
Anthropology will be the hard elective in alien school.
“Is the middle finger weaponized? Does it spray a venom perhaps”
“No, student Xeepzorp, it is frail and harmless like the others”
“Fascinating” -- Gallifreya
Ever since humans joined the Galactic Alliance, the Ask An Expert Anthropologist app had been rising in popularity. Humans could be relied upon to be confusing.
Humans from Britania lived on tannin solutions, and never said one word where ten could be found to dance around it. Conversely, humans from N'oz had the planet-wide tradition of 'bullshitting' anyone who wasn't from N'oz.
Other cogniscents in the alliance had to understand that the Britanians weren't hiding anything, and the N'ozzies were not malevolently lying. Or that the Amitans thought it was polite to talk to another cogniscent in that cogniscent's language.
There were entire threads dedicated to common human gestures, and which ones were rude. And sometimes, there would be explanations as to why those gestures were rude.
Most of those discussions devolved into puzzlement concerning the species-wide apparent fear of their own genitals and the act of reproduction. There was even a treatise on why pictures of genetalia were the worst of ice-breaking stratagems amongst many humans.
Excepting, of course, the humans who came from the very permissive colony of Friluv.
No origin planet was a monolith, but most cogniscents agreed that things would be much easier if the humans just made up their collective minds.
 Spoilers: it's most of them.