The song "Sad But True" was Metallica's 5th single release of the black "Metallica" album.

Album:
Metallica

The song live:
Since its release the song "Sad But True" has always been a fixed part of Metallica's live show.

The inspiration:
Hetfield has been inspired from an old Anthony Hopkins film called "Magic" to write "Sad But True". The idea of that movie is the persons duality from Hopkins and his hand puppet relationship.

The sample:
Kid Rock sampled "Sad But True" and used it for his song "American Bad Ass".

Song Interpretation (assumed):
It is about your evil part which tries to take the control over you.