This kinda sounds like “The Good Place”. Kristin Bell is a pharmacy’s saleswoman who wakes up in heaven and is mistaken for a lawyer. I haven’t actually seen the show, but I read the Wikipedia page and it sounds right.
Also, after a quick Google search, the Ariana grande song you mentioned is listed as being in episode 1. Hope that helps!
Disclaimer, I had horses in my youth, however I am not an adult horse person.
The answer to a lot of your questions is that a reasonably well trained (and well tempered) horse should let most anyone ride it. Horses are pretty smart and can definitely get some anxiety if someone completely new just shows up and tries to ride them, but again, if they are well trained they know that they have a job to do and they do it.
I can’t speak specifically about if a horse watched its owner die how it would react, so I’ll lean into your western scenario. If someone walked up to me and shot me with a gun in front of my horse, and my horse was not familiar with gun shots, then the horse would probably get spooked and run away. Horses are flight animals and once they’re spooked every instinct they have tells them to run.
As for telling at a glance how “obedient” a horse is, I can only say that I personally am not so skilled with horses that I could tell that. I can get a read on a horse’s current mood based on how it reacts to me, but that involves interacting with the horse a bit and I can’t say I’m perfect at it. Every horse has a different personality, similar to people.
Hope that at least gives you some answers!
One of the big things I don’t see mentioned here is that while the “active ingredient” in the medication is the same, all the other stuff in it is not. This also includes the binding agents that hold the med together and also the release mechanisms that control how/when the medicine is absorbed into your body.
For example, generic extended release amphetamine salts don’t release into your body in the same way Adderall XR does, despite being the same medication. While the patent on the drug has expired, the patent on the proprietary release mechanism has not expired. So generics can’t copy it. This could cause the generic to not work as well for some people, or some people could have a reaction to those different ingredients.
Edited: fixed spelling