You, a minor god, have grown bored of waiting for the next step in evolution. The other gods are tired of your complaints so they allow you to make one minor improvement to the human species. What change do you make?

When you scratch an itch, it actually disappears.

Give everyone the ability to change their skin color at will.

It’s a threeway tie for me:

Option 1) Everyone now has a minimim IQ of 140.

Option 2) Everyones empathy part of the brain increases dramatically.

Option 3) Addiction becomes impossible

I would adjust dopamine responses so things that are good for people, etc. Exercise, learning, and generaly improving themselves, hold a stronger attraction and pleasurable experience than those that cause harm, drinking, smoking, and drug use.

Nails stop growing just after they get even with the end of the fingertip.

… I hate clipping my finger nails.