There’s Less and Then More Less

    "I could care less",
Is baleful and grim
Especially when said
Bagman* flat,
With, maybe, a finger-jab in the chest...
A menace that leaves 
Not a flicker of hope, 
That he'll cut you some slack.
And there's no shade of difference, 
If the bagman says,
    "I couldn't care less."
Which is a tad more grammatical,
But likely means only 
The bagman passed English.

* Someone who collects money for racketeers.