I agree. There's nicotine in potatoes, eggplants, and green peppers...now most of us don't eat them in large enough quantities to get any effect from it. But what about a vegan or vegetarian?
PG if I remember correctly is used in the nicotrol inhalors by Phizer, also in hospital breathing treatments for pneumonia. VG is a humectant used in lotions, burn creams, it also replaces sugars in low carb/low sugar food products so we're actually using it daily outside of vaping.
Nicotine does pose risks if you have high blood pressure or some other condition in which constriction of blood vessels puts you at risk, but caffeine does that same thing.
That just leaves the flavorings. But let's face it, artificial flavors are in absolutely EVERYTHING we ingest so, as long as our ejuice is manufactured in a clean, safe environment we know what is in there. HOWEVER there are people with severe allergies to some flavorings artificial or natural so we should be aware of that when vaping in a public place where we'd get vapor in someone elses personal space like the doctor's office mentioned in another post, crowded subways, etc. I'd hate for my pleasure to cause someone else pain.