In modern pharmacology it's so clear that even if you have a fixed dose of a drug, the individuals respond very differently to one and the same dose.
Every summer my husband and I pack our suitcases, load our kids into the car, and drive from tense, crowded New York City to my family's cottage in Maine. It's on an island, with stretches of sea and sandy beaches, rocky coasts, and pine trees. We barbecue, swim, lie around, and try to do nothing.
Wouldn't want to write the X-Men, and I suppose the X-Men is the ultimate Marvel comic, and I really wouldn't want to go anywhere near it at all, although on the other had I wouldn't mind having a crack at something like the Punisher.