Word means to make something better or worse? [closed]

Solution 1:

Consider heighten:

• Make or become more intense.
  ‘the pleasure was heightened by the sense of guilt that accompanied it’

_Lexico

An example for happiness:

For example, someone who says they have a good sense of humor could try telling jokes to lighten up business meetings or cheer up sad friends. This habit, too, seems to heighten happiness.
_{Live Science}

An example for sadness:

As women age, many go through the emotional process of a life review (measuring what they’ve done in their life as mortality approaches), which can heighten sadness.
_{Psychology Today}