A study from 2014 found that people predicted that having a conversation with a stranger while commuting would not be as pleasant as keeping to themselves.  It turns out an experiment found the opposite.

One group of participants was asked to strike up a conversation with whomever sat down next to them on a commuter train while the other group was asked to keep to themselves per usual.  After their train rides the group that conversed with strangers reported a higher level of happiness than those who kept to themselves.  This result is consistent with other studies that have found that creating more social interactions leads to happiness, even if they are one-off weak interactions with strangers.

It turns out we are social animals.  Try increasing your interactions with strangers and see how you feel.

Source and more details here: https://www.nytimes.com/2014/04/26/opinion/sunday/hello-stranger.html?_r=0