I'd make the air unbreathable for idiots.

Probably a good thing since it's what I'm studying though higher level physics is pretty terrifying awesome too. But yeah, as TLB said, it's all the same once you get down to the nitty gritty, just a different scale. And on the note of what TLB said, I think that might be the first suggestion that wouldn't end in the death of everything, rather it'd actually be useful. This is of course assuming it didn't just randomly happen to things at room temperature but instead required some fairly complex process that's just less prohibitive than it is now.

But how would you breathe then?

Trolololol

No gotcha, the real question is; How would YOU breathe?

That's funny you see because Lizzrd took Gotcha's joke and then repeated it a single post later without changing anything at all.
True comedy genius right here.

Come on, you can do better than that, Lizard.

Edit: Okay, on topic then. Lower gravity. I want to jump to work.

I wonder how much of an effect on our bodies that would have, considering we've had this gravity since earth grew to the size it is today.

I know that being in low-to-zero gravity environments messes with Astronaut's bones
You could probably find out a good deal more about the effects of low gravity on a person by researching in that direction, I expect it's something that's already been quite well investigated (though obviously in non-human animals rather than people)
Here's some research on animal subjects

If i want to ♥♥♥♥ with everything: make nitrogen nourish flames like oxygen does. Cue matchsticks turning into incendiary bombs.

Otherwise i'd probably change Earths gravitational acceleration to 10 m/s^2, just because 9.82 is such an ugly number. It's only a 1.8% increase, so it's not like we'll suddenly turn into volus.

Or maybe make water superfluid, just to see what happens.

or maybe what TLB said because that'd actually be really useful

Admirable work ethic, still attending while the earth freezes over, drifting away from the sun.

He didn't say anything about sun having lower gravity now, did he?

he said 'lower gravity', as in... all gravity, i assume. which, really, would probably prevent planets/stars from ever forming in the first place.

Lower gravity in general wouldn't neccesairly disallow stars to form, would just make them form slower/end up smaller.

All you'd need to do to make earth have lower gravity (parsing this to mean lower gravitational force upon the surface denizens) would be to lower its overall density. So take out some of the heavy metals down in the core, bam, instantly lower gravity.

We could always need more spaceships!