Wearing dark glasses makes people think they can get away with cheating. - Darkness Increases Dishonest Behavior

Lonely people are unhappy, but small talk doesn’t help at all.  Exchange of interesting information (including gossip) makes people happy.  You can expect someone whose socialization is entirely small talk to be as miserable as someone who is completely alone.  Disclaimer: I think you can trust self-descriptions of happiness only as much as the interviewer isn’t someone the subject wants to impress, but perhaps social scientists know how to compensate for that effect - Eavesdropping on (un)happiness