Itachi says really vague weird shit.
Sasuke has picked up that habit, so he also says really vague weird shit.
They learned it from Madara who says the most vague, weird, shit
Shisui is the only one who understands what the hell their talking about it or alluding to.
Obito is perpetually freaked out™ by it
When Obito and Shisui hang out they have chaotic dumbass energy.
Birthdays and holidays are big events, you better be on a mission or dead if you miss them.
Everyone celebrates one day for all the birthdays of that month. But each family also has their own parties too.
Contrary to popular belief the Uchiha have a greater dislike for the Hyuuga, rather then the Senju, because of the caged bird seal.
The Uchiha clan as a whole raise children together, to help the parents and to form strong bonds. It's not unusual to see a group children toting after one adult.
Everyone is "Brat" to Madara, no exceptions. Izuna? Brat. Itachi? Brat. Fugaku? Brat.
The Uchiha have their own primary clan language, like most other old clans, that is taught before the common village language.
The language itself is very intimate in nature so it translates poetically (ex. Madara referring to fighting as dancing)
It's also regarded as the most difficult clan language to learn as a non native speaker.
Kakashi is considered an honorary Uchiha due to having Obito's eye.
Obito has taught Kakashi some of the language. But takes pride in being so much better at it even though he's a native speaker so Kakashi says it doesn't count.