What is Tet and what are two reasons that it is important?

Tet is the Vietnamese New Year. It is 1975, the Year of the Cat. To celebrate Tết, the lunar new year, Hà’s family eats sugary lotus seeds and rice cakes and wears new clothes; everyone must smile. Hà is learning how to embroider and raise her papaya tree. Her mother says one of Hà’s brothers must wake early to bless the house, because only male feet bring luck.