It's true. Or actually, the reverse is true: kids who express gratitude are healthier. So there. A new study reports that kids who took place in daily gratitude exercises were more alert, more determined, more enthusiastic, more attentive, and more energetic than kids in a control group who focused on their daily hassles.
I think also it gives kids a better connection to themselves and to their world. My kids, though they don't write thank-you notes, express gratitude to themselves and to the people in their lives on a pretty much continual basis. "Thank you" is a part of our lives as is simply expressing gratitude for what we have and who we are as people. Most of the time anyway.
Thinking about what's good in their lives makes kids more resiliant and more able to deal with setbacks when they occur. And while I don't necessarily agree with the idea of thanking someone for an awful gift that's inappropriate, clearly doesn't fit etc, I do think it's necessary to acknowledge the time, effort, and especially the love that went into that gift. And to do that, kids need to create an understanding, at whatever level they can, of other people and how they feel, which sometimes trumps complete honesty.
So how to create a grateful kid? Little kids can and should be taught to say thank you and please, but more importantly if there is an overall air of mutual respect in the house they'll catch on eventually. Talking about the blessings in your own life as well as the setbacks, or even better finding ways to see those setbacks as blessings, is also is a wonderful way to model real gratitude for your kids.