This is Houston. This is the 4th biggest city in the United States. So no, we don't all live on farms, we don't wear cowboy hats, and the only mustang I own says "Ford" on it. Nor am I a redneck, so don't immediately assume any of the above about anybody, because you're going to get strange looks if you do.
It's a big city, only slightly smaller than Chicago, and while we're friendly, there is no way in hell majority of the people know the entire city, so don't get pissed when you're talking about the northwest side of town when I live on the far east side and can't give you proper directions.
We have a lot of mexican food restaurants, and some very good ones at that. And we call it simply that, mexican food. There is no "Tex Mex" food and you've immediately given yourselves away as a tourist if you say that.
The Galleria is awesome, the museums are equally as cool, and the zoo is alright. I used to work at Space Center Houston for a few years, which is the official visitor's center for the Johnson Space Center. While NASA is infinitely awesome (as is JSC), our crappy visitor's center infinitely sucks, for the most part. There really isn't much cool to see, since our bosses won't let us show you, and consistently get non-space related exhibits. But then again, I'm slightly bitter about that place
Galveston is cool if you like brown water and random touristy shops. Oh, you mean you don't like that? Cool, me either. ...But truth be told, Moody Gardens in Galveston is worth checking out.
We're all mostly friendly people here, so try to be courteous back. It will take you a long way.