A study at Wake Forest University in North Carolina found that how we perceive other people mirrors our own state of well-being.

Participants who tended to judge others positively were found to be more happy, kind-hearted and courteous themselves. Viewing others negatively reflects self-centered and antisocial tendencies in ourselves (Richard Alleyne, "Happy People More Likely to See Others as Happy," Telegraph.co.uk, Aug. 3, 2010).

Developing friendships requires a positive outlook and an eye for the good in others, which, in turn, makes us friendlier.