Last week, on Last Week Tonight, John Oliver talks about PFAS, which was very interesting. Not only teflon, but all kind of repellent fabrics like Gore-tex:
H2O is good; remove one atom, get explosive H2; add one atom get the bleach H2O2.
For chirality: S-penicillamine is an anti-arthritic, R-penicillamine is highly toxic[0] (I was going to use thalidomide as my example, but that turns out to be something which changes between both chiralities inside your own body).