Are you working, or are you at work?

“And yet, I haven’t stopped shooting heroin.”

And yet means “in spite of all that.”

“You know I’m allergic to dogs, and yet you never vacuum your car out? I’m changing carpools.”

“I’ve heard a lot of bad stuff about heroin, but in spite of that I haven’t stopped shooting it.”

“And as of yet, I haven’t stopped shooting heroin.”

As of yet really means “up until this moment,” in other words it means nothing. The present is by definition an “as of yet” thing, so all statements about the present include that idea. These mean the same thing:

“I haven’t stopped shooting heroin.”
“I haven’t stopped shooting heroin yet.”

Yes, the second one seems to imply I may soon stop, but if you think that sentence means something different from the first, you haven’t known many junkies.

There is a musicality in speech, and whether purists like it or not “she loves you yeah yeah yeah” sentences are not quite the same without the yeah. If introductory verbal grunts like well and inane phrases like “when all is said and done” were simply wrong, English speech wouldn’t be as larded with excess verbiage as a junkie’s bloodstream is with endorphins. It must meet a need essential to the use of language, no matter how little sense can be made of it in textbooks.

In answer to a simple “have you stopped shooting heroin” question, these mean the same:

“No.”

“No, I haven’t stopped, not since the last time I checked, anyway. Why do you ask? Have you got some heroin you don’t know what to do with?”

Language is a medium, not an end in itself. Which of the two above sentences conveys more about the human condition?