Informality: The U.S. American lifestyle is generally casual. You will see students going to class in shorts and t-shirts. Male instructors seldom wear a tie and some may even wear blue jeans. Female instructors often wear slacks along with comfortable walking shoes.
Greetings and farewells are usually short, informal and friendly. Students may greet each other with "hi", "how are you"? and "what's up"? The farewell can be as brief as: "See you", "take it easy", or, "come by some time" (although they generally don't really mean it). Friendships are also casual, as Americans seem to easily develop and end friendships.