Most government employees are not allowed to accept gifts. Do not be offended if someone cannot accept a gift. Cash gifts are never appropriate. It is considered rude to stare, ask questions or otherwise bring attention to someone's disability. Smoking is very unpopular in the United States.
Restaurants have separate smoking and nonsmoking sections.
Public and private buildings may ban smoking except in designated areas. Some people do not allow smoking in their homes and will ask you to go outside if you want to have a cigarette. Never smoke anywhere without asking permission from everyone present. Names are not held as sacred in the United States. Someone may mispronounce your name and laugh a bit as they do it.