Customs and habits of usa

Hygiene
Spitting Spitting is unacceptable in any public setting except for baseball players on a field. If you have a cold and cannot avoid spitting up phlegm, use a tissue and then throw it away.
Public urination and defecation In the United States, public urination and defecation is illegal and very much frowned upon unless you are in a wilderness area-it is considered a health hazard and potential scenario which will anger locals, since they do not even allow dogs to defecate unless the mess is cleaned up. For example, if two parents encourage their young child to drop his trousers and defecate on the sidewalk, it is a certainty that they will be stopped dead in their tracks, the local police will be called, the policeman write up a report and hand them an order telling them they must report to a judge, and that judge will most likely slap a very heavy fine on the parents totaling thousands of dollars, not to mention giving them a good dressing down in front of the entire court. Foreigners will not be given clemency in this scenario, since it is expected that a child should be potty trained sometime between age two and four. 

If a small child needs to relieve him or herself, take him or her into the nearest bathroom (most restaurants and public buildings will allow it regardless of whether or not you are a patron and few managers turn away the desperate) and assist the child if needed. If traveling with a baby, most restaurants and publicly funded places like museums and monuments have bathrooms that include a place to change the baby's diaper and clean him/her off (split pants are very impractical in a climate that can get extremely cold or extremely hot, sometimes in the space of one day.) Wet sanitary wipes designed for baby are available in any pharmacy, supermarket, or gas station, and diapers in the first two of these.

Chewing with your mouth wide open Generally, an American will forgive you for the occasional slip of the mouth opening while chewing one's food, but generally don't like it when a person chews with their maw wide open and may or may not be talking. It will distract them from most of what you are saying, so kindly chew and swallow first.