Fa-la-la-la-la, Christmas is here! There are a lot of ways to get into the holiday spirit: You can decorate a tree, bake Christmas cookies, exchange gifts at a white elephant party—the list goes on.

The holiday season is supposed to be a time of joy, unity and general well wishes. But let's face it: for most people it's impossible to be merry and bright 100 percent of the time. For as happy of a ...