I think this situation was the result of inadequate assessment of "Cruella's" training. The vet should have concluded the training with "Cruella" going through the process from loading the syringe through injecting the insulin to properly disposing of the used syringe. The 'patient' should not have been returned to the care of "Cruella" until she was proficient in this aspect of being a caregiver. "Cruella" may have seen the insulin level at 18 units but did not notice the plunger was at the 18 units and the syringe was filled with liquid. Your contradiction of her recollection had her totally tuning out your explaination. She would only have listened to the vet or someone she recognized as knowledgeable in the medical field.
Next time, wear a lab coat with your name embroidered on it and she'll believe every word you speak.
@zeeglen: Remember the old TV series "The 6 Million Dollar Man"?
The thing that always gave me pause for thought was that they had only replaced one of his legs, but he could still run at 100 miles an hour (or so) ... how did his flesh leg keep up? It would have made more sense (but not looked as cool) if he had hopped on his mechanical leg like a turbo-powered pogo stick LOL
@David: It raises questions about the quality of the educational system amongst other things.
It's like they say: "Common sense isn;t as common as it used to be"
The thing is that I've come to realize that a lot of things I find easy and take for granted, many other people have trouble with. It doesn;t mean they are stupid, just that they have a different way of looking at the world.
I hope I don't start something here, but I did hear once that being able to envision things spatially is a trait that is stronger in the human male than the female. I forget what trait is stronger in the female, but there something comparable in their favor.
This is why mem TEND to be better with maps (I can read a map upside down and don't have to orient it a specific way), terrain following, and a general sense of direction (but I find this one is not as general as the others).
Notice, I am generalizing here and there are NO absolutes (so don't shoot).
@Bert.....similar feelings, and I feel you have to be patient with people like that - no one is perfect (not even me :-) and if you treat people like you would like to be treated, you can't go too far wrong. I think Max did so in this case, and I guess superheroes can get their satisfaction from a job well done, even if they get no thanks.
@Zeeglen - I am in awe of people who are so observant they pick up things like your examples. In this month's caption comp, Betajet picked up that a real die would not have the 3 and the 4 on adjacent sides... (sigh....there's so much to learn.... :-)
@Bert I too get impatient when confronted with incomprehensible cluelessness
Good example! And as David said it raises questions about the quality of education for even basic technical knowledge - a couple examples straight from Hollywood:
In the movie "Dolores Claiborne" there is a full moon one evening. The very next day there is a total solar eclipse. Duhhh
Remember the old TV series "The 6 Million Dollar Man"? Even as I kid I got a good laugh when a woman was trying to start her car, the engine cranked healthily but no ignition. The "hero" opened the hood and using his super strength fixed the problem by tightening the loose battery connector.