Thanksgiving is a traditional holiday in many countries, but especially in US and Canada.
This tradition started in 1621 when some UK pilgrims went to the “new land”, where nowadays is US, to celebrate a great harvest season at Plymouth. There were about 90 native aborigines (the Wampanoag) that helped the pilgrims with agricultural techniques. The pilgrims, considered the new Americans, were celebrating the God’s charity to produce some food to them eat because in that time, there was a strong winter period and more than a half of them died for the worst winter they passed by.
From that day on, it’s common in US the Thanksgiving Day and they take this seriously? Every year the whole country stops and offers food and thanks to the harvest and express gratitude for everything. This celebration happens on the fourth Thursday of November in US, but this day just became official in the beginning of 20 Century. In Canada this celebration just had a official date in the end of 19 Century, with the World War I.
The first thing related to food that come in their minds are Stuffed Turkey, Mashed Potatoes and Pumpkin Pie because is a traditional food in Thanksgiving’s celebration – as chocolate is eaten at Easter for us, Brazilians.
In Brazil this religious/thanking holiday is not common and that’s why we don’t have it here, but we do have some catholic holidays like “Nossa Senhora Aparecida”, more known as “Children’s Day”.
Every American sitcom we see, there’s at least one episode about Thanksgiving. As example there’s one episode on ‘Friends’(here) that shows perfectly how important it’s to them, how sad some of them became when what they planned got wrong. Other example is in Gossip Girl (here) where one episode is just about Thanksgiving and shows exactly how much they expect for the Thanksgiving night and the family/friend’s meeting. How anxiously the Americans get the whole day: they just have to focus on that, get dressed up, make delicious traditional foods and meet the family and friends at night. It’s the tradition!