Science might have an answer to the question of our age - why old people think youngsters are so damn angry and outraged all the time.
It's because their default position is to think everyone's happy.
Nearly 10,000 people - the youngest 10 and the oldest 85 - were showed faces of varying emotions, to see how well they decoded facial cues.
Researchers at Harvard University's McLean Hospital found the older the person was, the less likely they were to notice when someone was angry or fearful.
"We found that sensitivity to anger cues improves dramatically during early to mid-adolescence," said Lauren Rutter, who led the study.
"This is the exact age when young people are most attuned to forms of social threat, such as bullying. The normal development of anger sensitivity can contribute to some of the challenges that arise during this phase of development."
But as they age, they lose this sensitivity - while retaining another.
"We see declines in many visual perceptual abilities as we get older, but here we did not see such declines in the perception of happiness," said Dr Rutter. "These findings fit well with other research showing that older adults tend to have more positive emotions and a positive outlook."
Which perhaps contrasts sharply with the experience of younger generations, who are living with stagnant wages, rising housing costs and more exposure to the world's injustices through social media and the internet.
The McLean Hospital research was published in the Journal of Experimental Psychology: General just as Newshub launched its Age of Outrage series, looking at what's driving society's apparent descent into outrage in recent years.