> if you can do the worst “bad” thing possible, you can also do the best “good” thing possible

You say this like it's a truism, but I don't think it is. The bad things may be categorically easier than the good things. It's easier to destabilize a delicate system than to stabilize it. It's easier to break something than to fix it.

Suppose it matters what order you do it in.

The best good thing possible for humans who are all suffering from an extremely painful, incurable disease might just be ending that misery.

The worst bad thing possible in a perfect utopia might be a minor inconvenience comparatively.