It really depends on the acculturation level of the individual to our mainstream U.S. culture. When I first arrived in the U.S., I was amazed to see that there were no visible barriers between people. Anyone can strike up a conversation with another person regardless of age, class, gender or status differences. People smile and laugh during their first meeting with others. It appears that they have known each other for a long time.
People display pictures of their wives and children in their offices.
To my surprise, many folks carry pictures of their loved ones with them all the time. They are eager to share those pictures even with a person they have just met. Informality reflects a value of mainstream U.S. culture. In many other culture, formality is valued. The Mexican, Chinese, Asian Indian, South American, and Arab cultures are more formal .