Just get up, right now, and go give a big smile, and maybe even a hug, to the first person you come across. If it's a family member, that's wonderful. If it's someone you've grown to despise, all the better. Trust me. Giving this random gift can be one of the best things you do this Christmas season.
Why are you still reading this? Go on! Step away from the computer... It's random-act-of-kindness time. I mean it.