Thanksgiving's been around for a long time in this country - since 1621, after the Pilgrims' first harvest. The party lasted three days, and was attended by 90 Indians, and 53 Pilgrims.
Up through the Civil War, it was an unofficial holiday, marked individually by presidential proclamation (and which proclamations always referred to a duty to be thankful to God...food for thought for the 'exclusion clause boosters). It was often invoked to commemorate military victories, such as the 1777 victory over the British at Saratoga.
In 1863 President Lincoln made it official, and set the date as the last Thursday in November. The tide of the Civil War had turned at Gettysburg earlier that year, and he felt it appropriate to celebrate.
In 1939, FDR realized that November had five Thursdays. Since the country was still in the grip of the Depression, he wanted to increase the Christmas shopping season, and moved it to the next-to-last Thursday of the month.
Still with me?
Finally, in 1942 Congress passed a law making Thanksgiving the fourth Thursday of November, period.
But that wasn't the end, and some states continued to observe the "last Thursday" tradition. Texas did so until 1956, but Texans do go their own way.
So there it is - a holiday that began as thanks to the Almighty, was invoked for military victory, and eventually was shifted to enhance the Christmas shopping season.
So don't feel guilty about celebrating the fact that you have enough to eat, that you live in a strong, kick-butt country, and that you're going to go shopping on Friday.
Do thank God...but remember that these things we do are things for which we should be thankful, too.