"always look on the bright side of life," advises a tin pan alley standard. the lyric is promoting coping.

The answer is Emotion-focused coping. This targets to decrease and manage the intensity of the negative and distressing emotions that a traumatic situation has caused rather than solving the problematic situation itself. These coping strategies therefore help people feel better but don’t solve the source of our pain.  This coping frequently gets applied when the problem is uncontrolled like terminal illness or sudden and they need to try to handle and accept the situation.

a: social security and social programs