Am I understanding correctly that they found they can give you this chemical and then if you experience negative things you won’t remember them (or you will but without negative connotations)?
Of course it's more complex than that since most of those also make it easier to keep you under.
Sometimes, anesthesiologists will give opiates so that you don’t wake up abruptly in pain, or give benzodiazepines so you feel less anxious afterwards. Depends on what they did - if you had a dislocated shoulder, the pain is much less once it has been ‘reduced’ (Put back), so you probably wouldn’t have (too) much pain, relatively speaking, once you wake up. But if someone just cut open your abdomen, you will have lots of pain on waking, so makes more sense to give some opiate beforehand, to make your wake-up ‘nicer’.
Propofol also tends to lower your blood pressure a lot, so some docs feel you can get the same level of sedation with less low blood pressure by giving a bit of benzodiazepines + propofol
My moment was not propofol but another medicine for nausea/vomit - it worked in seconds just when I had resigned myself to throw up. I was shocked. How?
https://en.wikipedia.org/wiki/Ondansetron
Usually nausea is caused by the perception that your body "doesn't feel right." Serotonin is responsible for the feeling of wellbeing. Just so happens that subreceptor 3 is more about well being feeling of the body :-)