The U.S. Department of Agriculture has tried some difficult things before, like its various attempts to get kids to eat vegetables, or its effort to get people to stop eating cookie dough.

But USDA this week made a recommendation that could be virtually impossible to follow — that families should only talk about happy things when they eat. USDA made it sound simple in a Christmas Day message:

Focus on each other & talk about fun, happy things at mealtime. Make your meals stress-free. http://t.co/DAWgK6ooV8

— ChooseMyPlate.gov (@MyPlate) December 25, 2014

While USDA usually uses its MyPlate email service to offer advice about what foods to eat, it has been known to stray into issues not normally associated with farm policy, such as advice about getting exercise. Calling on people to only discuss "fun, happy things" at mealtime seems to be another example, one that is likely to be ignored by families who often use mealtime to talk about grades, money, politics and other miserable topics.

It also dismissed the reality of having parents, aunts, uncles and other family members over for the holidays, which is certain to lead to non-happy talk, especially if they've been visiting for more than a week.

The tweet linked to a page that offers more detailed advice about how to talk to kids about food and other things at the dinner table. One of USDA's suggestions is to ask the kids, 'What made you laugh today?'