List 5 things which are basic common knowledge in your culture, which people outside are unfamiliar with. This is not about obscurity, but something everyday to you, that others go "bzuh?" at.
So, this is about Texas stuff.
1) If you order tea, it comes in a glass, and it is iced, and you must specify "sweet" or "unsweet". If you want a steaming cuppa, you have to order "hot tea".
2) High school football is THE premier sport in most of Texas, with more loyal fans than the NFL teams have.
3) Austin TX is widely agreed to be the music capital of the world.
4) Texas is not, under the law, a legal member of the 50 states. Texas was annexed via a joint resolution of Congress, after an invasion by the US which forced Texas to become a part of the US, and in 1861 the people of Texas, by a HUGE majority, voted to NOT become a US state.
5) Dr Pepper was invented in Waco, TX, and can be found in every restaurant in the state, near as I can tell.