I mean gravity on Earth ofcourse. I wouldn't really care about changing the gravity on other planets and stars, since I won't be visiting them anytime soon.
Anyway, yeah, atrophy is a ♥♥♥♥♥.

Chemistry is just applied physics.

I'd change the laws of thermodynamics. And make it possible for machines to be more than 100% efficient. Free energy for everyone.

What are you talking about chemistry is not part of everyday life!!1

I'll change math so 2+2 does equal fish.

Math is not physics. Physics uses math, but it's not physics.

Math isn't physics, but physics is math.

And physics is just applied math, like the conversation suggests. The one who should be standing in the shun corner is stats. That said, I'd say chem and phys are more the same thing on different scales rather than applied versions of each other. Here I'm talking about physical chemistry and quantum mechanics rather than synthetic or analytical chem.
And oh god I can't even imagine what the real consequences of that would be. But yeah, more than 100% efficient heat engines would be cool though I'm sure we'd all be long exploded if energy could just be created.

I was just chatting with my coworkers about this sort of crazy/stupid "what if" scenarios (because this is totally the sort of things meat cutters typically discus in the refrigerated nether regions of a grocery market.) Except where our conversation went was much, much less educated. Someone tossed out "replace gravity with gravy," which, I know, is silly to the point of not applying oneself. But it did get me thinking about what it'd look like to switch out a force like gravity with a tangible object thing. Like gravy.

But if I could change one thing in physics, I'd make helium much more significantly lighter than air. For all those "make stuff float" ideas.

Oh, another thing I would do is decrease inertia. Slowly. Over time. It would make stopping much easier.

Gravity no long applies to clothing.
Or anything inside them.
That is all.

So... Zero gravity boobies?

I would make absolutely every material in existence a superconductor at room temperature
What could go wrong

That would be an unintended but not unwelcome side effect.
Was thinking put on a t-shirt and jeans, get some big fake wings, and go flap your way into the sky.

Flap flap flap flap....
"Who's that naked person in the sky?!"

My change is....
The definition of a vacuum would be an area filled with breathable gas (for humans, anyways). At Earth pressure. This would make "space" travel far easier, as fuel would be anything that could burn on Earth.

Feasible, no?