Worldbuilding: The Rhythm of the Year

  This time of year can be tough for my family for reasons that will seem a little odd to most people.
  It is because of the calendar.
  You see, to us it is not the Christmas Season, it is Advent. We don't put up ornaments or lights or a tree until December 24th. Then we go to the Vigil Mass for Christmas. Then the Christmas season starts and we celebrate the Twelve Days of Christmas until Epiphany, then we take down the tree but leave up the lights until the Christmas season ends with Candlemas on February 2nd. I finally take down the lights on February 3rd.
  Why?
  We're Catholics with traditions from the Old World.
  In the liturgical calendar the beginning of the new year (for the Church) is the beginning of Advent. Advent begins on the Sunday closest to St. Andrew's Day (November 30th) which is the 4th Sunday before Christmas, of course. Advent is traditionally a time of penance and fasting in preparation for Christmas, almost a sad time as we reflect on why Christ had to manifest. Once Christmas actually arrives then we celebrate, decorate, and play Christmas music.
  Why is this hard? Look around! For almost everyone else the Christmas music starts the afternoon of Thanksgiving, the tree and lights go up the weekend of Thanksgiving. The music stops on December 26th and the tree and lights come down around New Year's, if not before.

  No, this is not about me telling you that you are doing Christmas wrong. You aren't. You just have a different calendar.