In the presence of
unhappy people,
happy people
can unwittingly make
the unhappy people
envious
of
their happiness,
hence
unhappier.

In the presence of
unhappy people
who are
envious
of
their happiness,
kind happy people
should, therefore, try to be
less happy
in order to make
the unhappy people
less unhappy,
hence
less envious.

In the presence of
happy people
who have deliberately made themselves
less happy,
however,
unhappy people
who have unwittingly been made
less unhappy,
hence
less envious,
through
the kindness
of the originally
happy people
who are now
less happy,
might take the opportunity to try to be
even less unhappy,
hence
even less envious,
in order to make
the happy people
who have deliberately made themselves
less happy
even less happy,
hence
envious,

but that would not be
kind.