so what are the really important rituals and traditions in the chinese cultures?

There is a legend. In ancient times, there was a monster called Nian. It came to make trouble frequently at New Year's Eve (Jan. 29 or 30 on Chinese lunar calendar). The villagers couldn't cope with the monster. So they left their homes to avoid the monster. Some day, they found out that the monster was afraid of red color, firecrackers and light. Then the villagers started to set off firecrackers and stick red couplets on their doors to scare away the monster. Later, it gradually became a festival.

Today, it has become the most important festival. No matter how far they are from home, they go back to spend the Spring Festival together.