Japanese people prefer to maintain harmony and often hesitate to say "No." This sometimes causes trouble with foreign people, who don't understand that they are just trying to be polite.
In early April, cherry blossoms come into full bloom everywhere in Japan, and a lot of people get together at parks, temples and shrines to have parties under the trees. This custom is called "hanami" or flower viewing.
It has been customary in Japan to send greeting cards on New Year's Day, wishing your friends, relatives or colleagues a happy new year. With the spread of cellular phones and the Internet, however, this old tradition is gradually being replaced by online greetings.