https://www.theguardian.com/science/2021/jan/24/the-five-emotional-contagion

The idea that emotions can ‘spread’ from one person to another seems to be taking hold in the psychological world

Last week, scientists from the universities of Oxford and Birmingham published research describing how teenagers’ moods were affected by those of others around them – and that bad moods were more potent. They also found that when a teenager “catches” a low mood from a friend, the friend’s outlook becomes more cheerful.