Why are things different when you cross the U.S to mexico border?

Things are different first of all because it is a different country.Another reason why it is different is because of the people. For example the people in the United States [a majority of the people] are American, and in Mexico they are all Mexican. Also Mexico is a third world country. In Mexico its not as clean as it is in the United States. Their buildings aren't as well constructed as ours here in the U.S, which is why most of their buildings fall apart so quickly. Apparently some of the people there don't know how to use the trash can?? Here in the U.S we have enough money to well construct our buildings so that they last much longer. We aren't as dirty as Mexico's citizens but we try our best to keep our country clean, And last but not least we all know how to treat our country with respect and to not liter. In conclusion you can see how different the U.S is way different from Mexico.