I’d give all annoying, biting and stinging insects a terrible fear of humans so they’d flee at the sight of us.
(Don’t want to screw up the ecosystem by vanishing them entirely.)
I’d change my name to “Melvin,” so people wouldn’t take me seriously. The Word of Melvin isn’t going to terrify anyone.
As it stands you can both do the former and the latter is probably already the case, so how about something more impactful on humanity, like making tags on shirts a illegal or making cans of soda unopenable in the workplace until you write your name on the can so I don’t have to spend 15 minutes every day listening to co-workers ask which Diet Coke is theirs (every day, literally).
Ooh, good one. The EU mandated the tags have to list all 24 official languages, so now you get three itchy tags instead of just one. 
Or at least print them directly on the fabric or put the tag down on the seam down by your hip. Anything to keep it off the back of my neck. I’ve ripped holes in dozens of shirts after having them for just a few hours and getting so annoyed that I tore it off (and ripped the shirt in the process).
I got some redemption when I learned that hypersensitivity, specifically with shirt tags, is a common ADHD symptom.
Every time you stub your toe, instead of shooting pain, it results into uncontrollable laughter for about 30 seconds.
I would smite the OP for suggesting I, the lord, your god, king of the universe, could ever be petty.
I’d wipe out mock strawberries. I thought we had an usual form of wild strawberry with yellow flowers in our new garden, but no. I tasted one once they ripened, in case the description was wrong and they were at all strawberry flavored, but no. They taste of NOTHING. NO TASTE! ONLY ZUUL!
First order of business: Find a way to house testicles inside the body. Maybe stick them where the ovaries live in females.
It’s not just their vulnerability to trauma - which I am not minimizing - but also the fact that they just hang there, getting in the way. The center-of-the-aisle cart leaver at the Piggly Wiggly is the Testicle of the Supermarket.
mmm
I’d make it so that when mosquitos bite you, it doesn’t make you itch. I’d enlarge the spectrum that human eyes can see, so there are more colors. I’d get rid of whatever genes cause the body to start producing hairs in increasingly silly places as it ascends into old age. And I’d get rid of that gene that some people have that affects how cilantro tastes to them, so I wouldn’t have to hear people complain that the salsa tastes like soap.
You also need make sperm less sensitive to heat. That’s why they hang around outside all the time.
Strengthen the human spine so that people don’t get lower back pain.
And fix the eyes. The human lens is badly designed and prone to rapid deterioration.
And make it so the usual sites of infection – appendix, tonsils, adenoids, gall bladder – don’t.
Body parts can regenerate. Especially teeth.
And no more cancer.
Somehow eliminating the need to clean anything, especially in the house. I don’t know how, abolish dust and grime, give every surface a perfect lotus effect, maybe even invent a perfect cleaning robot affordable for every household, but it should be done, and my life became much less miserable.
Cigarettes would be the cause of only one medical condition: Impotence. It would only take a few days to take effect, each cigarette causing a week of sexual inactivity, and it would be 100% effective.
Yeah, I think that’s pretty common knowledge. God (I) can change that.
mmm
How about making drugs (including alcohol and tobacco) non-addictive.
I think both male and female people would benefit from selective retraction of various body parts, kind of like an airplane’s landing gear, when having them out there on the outside is just plain inconvenient.
Abolish Mondays.
And the knee ligaments.