There is great overlap between regions, all driven by personal perception. Here are some good maps that show perception studies:
http://www.geog.nau.edu/courses/alew...pters/ch1.html
For instance, Ohio is both midwest and northeast. Texas is both south and southwest.
I grew up in northern Ohio as associate more with Great Lakes or Rust Belt than midwest... but if you live near the border of Indian that would be different. I now live in Austin and this is not South culturally but if I head to east texas it is.
Midwest typically means grain belt like Iowa, Kansas, etc. Then what is the difference between great plains and midwest? I imagine everyone has a different answer based on where they've lived and been.