It depends on where you are coming from.Let's say you are coming from Asia or more specifically from India.Here is what you need to know:Don't assume anything like we do back home in our country. I used to do that a lot and had to pay for it later here.Be on time wherever you have an appointment. Be it at Doctor’s, Dentist, or any other place.There is a concept of space in the west including America. Don't keep hugging, touching, crossing by close from people and touching others while crossing them.Don't break the queue. It is deemed disrespectful and unlike in many other countries including India, you will be called out by any individual there standing in the queue. Everybody is same in America and it feels that way too.If you are a first time student then your task is cut out. You need to care for a lot of things. It's completely different from India. Lectures happen on time. Submissions of assignments can't go beyond a prescribed date or hour of the day. No personal favors from the Professors because of your gender, caste, color, religion, personality etc.If you are visiting for the first time, make sure that you don't throw garbage wherever you like. Somebody will definitely check you in public and somebody can also report that to the police. Littering fines are really high in some places.No free perks in this country. You earn and you eat. Simple as that. Unlike in India where if you are a top government official or a politician, you don't have to carry your wallet with you anywhere because you seldom have to pay for anything.When you pass by anybody, most people will smile and say ‘Hi’ or ‘How are you?’. Don't be surprised. This is how everybody greets each other here. What a great thing to do.People will open the door for you or keep it open even if they are ahead of you. That's just how people like to help each other. It is not seen in many countries at least not in India.You go over the limit while driving, chances are that you will be caught and fined. Stay in the speed limit or just a few miles above it is also acceptable. Drink and drive has huge fines, never try that. Don't overtake too many times, the police is trained to catch such people.If you get into an accident on the road, don't keep beating the hell out of that person whether it's their fault or yours. In India, it is very common that whether it is your fault or not, you have the moral right to beat the crap out of the other person. Just like that. Here in US, you will not just be put in Jail, you could lose a teeth or two as most people are not that submissive.Keep walking on the road while crossing. Here in US, pedestrian has the right of way before anybody to cross the road. Don't try that on a freeway. No right of way there for pedestrians.Thanks for the A2A!