If no one ever said "thank you", it woul be sad because I'm convince that every people need to be thanked when they help someone else. It's a kind of gratitude and it's very important. Saying "thank you" is a way to show to other people that they did something useful and nice for you. If nobody said "thank you" some people would not help people because they would be afraid and disappointed to have nothing in return, even the magic words. Indeed, we're use to say to children that "thank you" is a magic sentence linked with "please". This is the foundation of the courtesy. Saying "thank you" is easy as ABC and important for public opinion, so we have to say it.
As far as I'm concerned, I think Thanksgiving is a bit like Christhmas. That's why, I would celebrate it with my near family, eating a feast all the day. At this feast, I would eat for instance fish, turkey, vegetables, fruits, pumpkin pie (just to taste it, I'm sure it's delicious!) ans of course chocolate ! Moreover, I would have presents like money just to go shopping on the black friday :)