What surprised me most, is that the different states differs such a lot. Well.. some, at least.
That has surprised people I've chatted with. I guess, coming from a different place, and also being on the look-out all the time, for new things, helps noticing that.
Of course, different states have their own way of handling things. In New Mexico, the road signs are blue with yellow text, which I didn't see on many places. Of course, various states has different rules and laws. In some you can only drive 65, in others 75. Some charge you $1,000 for littering the highway, others $5,000.
But, it's not really that I'm thinking about. It's the landscape and general culture, as well as a "feeling".
Even if I were in a part of USA that has essentially the same condition, it seems that the state lines has been drawn (with a ruler admittedly) in a general sense according to the types of the landscape. For some reason, if you go from Kentucky to Tennessee, there's a slight change in nature. Not dramatic, and it's slightly gradual, but, there's a change.
The other major thing being that, people in USA very much do like the neighbors, as well as being "proud" of their own State. In Kansas, and nowhere else, except the first 10 miles or so into Nebraska, they've got round fields, since they have the practice of placing one end of the irrigation in the center, and move it clockwise around it. In fact, I'm not sure I ever saw a field that wasn't like that, while in all other places, the fields were square. In Wisconsin, the barns had a brown silo. Every single "farm" had it. They had silos elsewhere, but not in that exact way and style. It's close between Texas and New Mexico, but the moment you got over the State line, you started seeing houses with flat roofs, "New Mexico"/"Mexico" style. Didn't see a house like those nowhere else.
All together making a different feel from state to state.