It’s a simple rule, and it’s an important one too.

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During the holiday season, we’re always searching for ways to impart life lessons to the children in our lives, to pass on through the generations the wisdom that’s been passed down to us. Thanksgiving, in particular, makes us sentimental about one important etiquette rule, and that’s gratitude.

Gratitude—a rule? Gratitude is both a rule and a practice. For us, Thanksgiving always prompts a reflection on the importance of expressing our thanks. (It’s in the name, after all.) Thanksgiving is about giving thanks for things big and small, tangible and abstract, expected and unexpected. It’s a good reminder to practice gratitude. And we should practice, because the research is in, and it says that feeling and expressing gratitude is strongly linked to greater happiness and more positive overall mental health. That’s one big reason to encourage gratitude, reward it, and reinforce it for yourself and for the children in your life. When gratitude is practiced, it becomes a habit, and when it becomes a habit, the daily positive effects only grow.

It's important to notice moments of gratitude, to take a moment to acknowledge and process them when they arrive. Gratitude isn’t just about feeling grateful, however; it's also about expressing and acting on those feelings. When gratitude is both a feeling and an action, it becomes a valuable exchange. Expressing and acting upon gratitude—saying thank you, writing a thank-you note, giving a gift in return—becomes a relationship-building exchange of positivity and kindness.

As described in a past Harvard Mental Health Letter, there are several practices you can implement in order to cultivate greater daily gratitude. These practices include writing thank-you notes, thanking someone mentally, keeping a gratitude journal, counting your blessings, praying, and meditating. We think that talking openly about gratitude and giving back by volunteering are also valuable ways to encourage feeling and expressing thanks during the holidays and anytime throughout the year.

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How do you practice and teach gratitude in your own life? What life lessons and etiquette rules are you encouraging this season?