[(JD)]

http://www.psychologicalselfhelp.org.../chap6_16.html

"The important point for the self-helper is that happiness and
depression are two somewhat independent dimensions--you need to
work on both decreasing depression and increasing happiness, if
unhappiness is a problem for you. Yet, it seems that trying too hard to
be super happy is like trying to be someone you aren't; that too may
be a bad idea. Instead, "To thine own self be true" while making
efforts to be happy: seek demanding, challenging work; exercise in a
fun way; do several pleasurable things every day and show your
happiness; nourish close relationships, and be good to others."

[(JD)]

Current research suggests a tendency towards depression is inborn
so that each of us probably has a set point for depression and on a
different dimension for happiness. Studies of twins and adopted
children support the inheritance notion. Of course, in spite of any set
point, radical changes in our lives can change our feelings. Someone
important to us dies and we are saddened for months, but eventually
we usually come back to our set point. Winning a multi-million dollar
lottery has drastic impact on our emotions but only for a year or so,
then we go back to our usual mood. Paraplegics return to their pre-
accident level of happiness after a year or two. Sure, there are some
terrible experiences so traumatic that some people can’t ever recover,
like the death of a child or a brutal assault. In the opposite direction, a
lonely person, who finds someone who really loves him/her, may be in
high spirits for the rest of his/her life.