First of all, everyone is smiling. If you do not smile, everybody will ask you what has happened. In the beginning you get tired of that but then you get used to it, but at first it seems strange as we all know that laughter without any reason... Still try to smile at least to avoid the stereotype that all Russians are angry and gloomy and with lack of sense of humor.
Then, they say hello to everybody in the street, to a shop-assistant in a shop, to a working man at a filling station... And not just say hello, but also ask 'How are you?' and in reply say that everything is fine. Many Russian brides that have come to the USA recently forget to ask how the person is doing. So you should say hell and ask 'how are you' otherwise you will look impolite.
They thank each other for every little thing. At first it irritates but then it's ok. Americans are extremely polite. They always say sorry even if there is not their fault.
Their sense of humor is a bit strange too - even not strange, but silly. You are likely to have seen old American comedies - these are their common daily jokes. If you crack a joke you must laugh yourself otherwise it's impolite.
Americans are great optimists. Their motto is 'everything will be fine'. Their favorite word is 'enjoy' and they try to enjoy every moment of their life.
What else can cause you bewilderment - clothes. In daily life foreigners, especially Americans, put on very simple clothes and it looks even negligent. Women in the streets can be a real shock - no wonder, that coming to Russia all Russian brides seem beauties to foreign men! Normal clothes for each day are jeans, a T-shirt and trainers both for men and women. In more cool weather - a sports suit. They very seldom put on something original and not typical.
Here in Russia the clothes are considered a symbol of material status, and there it is not like that, they should be convenient. As T-shirts, shirts and blouses are changed each day (you can't wear the same thing for two days running), it is necessary, that they are easy for washing and ironing. By the way, the majority of things, that we usually iron - such as bed-clothes, - they do not iron in general. If you have got used to carry clothes from expensive designers, it may seem strange to them, they are not used to paying $300 as some Russian people do. Even very very rich people there have got very simple clothes on them. There a car or a district where you live is considered a marital status. And to walk in your 30-bed-room house in Beverly Hills you may in a T-shirt bought for $5.