If you were God

[Sirion]

I would mostly do small things only to make people around me a little happier with themselves, since any big picture changes any normal human being could think of could inevitably ruin the world.

But I'd like to create another sentient race to live with humans. Maybe an elf-like race or anything like that. Different, not that much (like idealized elves that live forever and are wise and always caring about nature and stuff) from humans. Prejudice and sorrow would certainly rise (I like to think there would be people and organizations like Greenpeace trying to protect them too, like in Ditrict 9), but everything we have ever seen and known in our human-centric world would change forever.