January 1 was not always the beginning of the year--ancient Romans got their calendars going in March. The English did not take January 1 as New Year's Day until 1752. Presumably that was the year they discovered Champagne.
The making of resolutions is a custom that seems to endure. One that did not last was the bribing of magistrates--we are not making this up--which was abolished by law in 1290. However, you may still find someone in elected office willing, for old time's sake, to accept a packet of cash slipped under the table.
Enjoy the holiday. And should you find you have celebrated not wisely, but too well, take heart from the words of Jack Wasserman: "It is better to have a morning after than to never have a night before."