Why do people drink alcohol in Japan?

I post on May 22, 2006 in fact.

That is my homework of English lesson.
There are 3 reasons why Japanese people drink alcohol.
1st, they drink alcohol to relieve stress. They get drunk, complain about their lives, and make noise.
Then they drink to just enjoy drinking and eating.
At last, Japanese people sometimes drink alcohol to build a relationship. Traditionally, drinking alcohol has special meaning in Japan. For example, a new married couple drinks sake in shinto wedding. So some people gets angry at refusing their offering alcohol, because they they think it means to refuse building relationship with them. On the other hand, some Japanese cannot drink alcohol by nature. As a result, they sometimes get sick from social drinking.