I was born in California but we moved to Texas in 1974. So, allow me...
You know you're from Texas when ...
It's over 100 F for days or weeks and you just call it August.
Any social function must have beer, barbecue, and a country band. Where my wife grew up, it was the previous three, plus Bluebell Ice Cream.
You drink a soda.
you think anyone north of the Red River is a yankee.
When April through May is tornado season.
Though Chicago may be the Windy City, you know Texas is the Windy State.
You ain't somebody unless you have a 4 X 4 Crew Cab Duallie that gets 4 gallons to the mile. Even if you don't actually tow anything with it. And if you do, you can't drive under 80 mph.
You cringe when someone has a sharp twang in their fake Texas accent. It's more subtle than that and more importantly, the speech is slower, rather than affected by mispronunciations.
You greet people with "Howdy" and that's all that's necessary.
You know the Longhorns are the best, they just have not so successful seasons.
You've heard of Aggieland and Aggie Money and you know that book of jokes about Aggies are published by the Texas A & M Press.
You or someone you know has at least one horse.
You know at least a few words of spanish.
You have used the phrase "fixin' to" which means preparing to do something.
The last piece of deer summer sausage is worth getting in a fight over.
Labradors are everywhere. And Lab mixes.
You have a poker game (Texas Hold'em)
You have a dance (Texas Two Step)
You have some of the world's best barbecue (Sonny Bryant's)
You have Lake Texoma, third largest man-made lake. (Where, BTW, the state record catfish was caught with surf rod from where I usually fish in Hagarman Wildlife Preserve. 121 lbs!)
Don't forget Houston, seminal place of that little old' band, ZZ Top.
Dallas, home of the Dallas Cowboys, my favorite team since 1969, despite all of their troubles.
And, of course, you have the i-doggers that live here.