Piece Of Garbage
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'.
Some of our Coworkers sure are Trashy, but the way Barb treats other people, she really breaks the mold, for she is truly a Piece Of Garbage!