According to a recent yoga article I read, there are 6 benefits to gratitude. I read the lengthy article and can wrap it up for you in a few short bullet points.
1. It changes your perspective. It reframes your viewpoint.
2. Biologically, it heals you. Your neurotransmitters, hormones and tissues actually improve.
3. It gets you out of victim mode and feeling sorry for yourself. You complain less and bless more.
4. It attracts positive people and experiences to us. It is the law of attraction in action.
5. It grows you spiritually. Your awareness of being fully present expands.
6. It fills us up, calms our disparate energies and assures us we live in abundance.
My suggestion: If you are consistent in your practice, you will be happier. Give it a week beyond Thanksgiving Day and start in the present moment.