>>"extremely careless" and "gross negligence"
Not sure it's philosophical.
If you are distracted and run a red light, that's extremely careless, even negligent.
If you do it again the next day because it saved you so much time, but this time you mow down and kill three cyclists, then you're grossly negligent.
Seems to me that "grossly" negligent means you knew your actions had the potential to cause great harm, but deliberately went ahead anyway. Usually not that easy to prove unless you're a repeat offender, fwiw.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1