1. create/find/give people a single, unshakable, and perfect center (the same one, so no one could argue whose was better) to build their lives around, freely, which (since it was crafted to mold to human needs) everybody enjoyed and agreed was worth living for. It would be so unmistakably, infinitely valuable, beautiful, and worthwhile that not a single person doesn't want to build their lives around it, and infinite in the substance of what it can give, so that "more for me" doesn't mean "less for you" at all.
All peoples' self-worth would be tied up in this, so that differences in character, ability, etc, don't even cross peoples' minds as things by which you can judge people. Pride becomes non-existent, because the center of life does not reside within anyone. Thoughts such as "is it ok to let this person I'm talking to know X, or will it cause them to think worse of me?" and "is it socially acceptable to ___?" and the like vanish from everyone's minds. Greed and the subsequent wars cease, because all people already have the only thing worth having. A lot of other activity would cease, too, as people rested and simply enjoyed life, but that would be ok because nobody would want anything more anyway. Of course, things like advertizing, which prey on peoples' desire or more, have to vanish too.
2. I would give all control of nature to mankind, as if it were an ability just like walking. People (and animals) would look around and just see it as "something men can just do." I wouldn't feel bad doing this, because we wouldn't want to suddenly harvest everything for our own comfort (I imagine if you did this now, most people would make oil come together and fill up their jars, and things like that) if they wee satisfied outside of themselves. You would not have to struggle against the elements, though, so survival isn't an issue.