People who are worth less than a "Piece Of Trash" or / and "Piece Of Shit"

Depending on the context: A Piece Of Trash can be lower than a Piece Of Shit since "Shit" can be used for useful purposes such as Furtalizer.

But a Piece Of Shit can be lower than a Piece Of Trash.

In any of the above context, a "Piece Of Garbage" is less or lower than the the above.

Therefore if a person is a "Piece Of Garbage" their worth is the lowest on the 'Worthless Scale'.

When you eat dirt for the first time and leave your family to build a shack in the woods