1. Bring your bad-ass, Zika virus adjacent-ass kids and expect that since there are other adults around, you don't have to watch them
Maybe it takes a village to raise a child, but the village aint responsible for your neglectful-ass allowing your pinheaded seven-year-olds to slapbox by the flame pit. If being a parent is too difficult for you today, at least put a leash on those little motherfuckers or chain them to a flag pole so they don't knock over my plate.
2. Invite unvetted people
A counter argument could be that you could bring someone to the cookout specifically to vet them. And this is fine for people you just started "dating" and you want to see if they should be promoted up from "NetFlix and Chill" to "Boston Market Rotisserie Chicken and Fuck" status. But no unvetted work buddies or White people or anyone else if you're not sure how they're going to react to a bunch of swine-eating niggas outdoors.
3. Talk shit about whether a woman is "in shape enough" to be showing skin
No one gives a flying Trump toupee fuck about whether you think Kim is "too big to be wearing that onesie." And even less of a fuck is given if you personally haven't done a crunch or seen the inside of a gym since Michael B Jordan was Wallace, with your hypocritical critical bitch-ass.
4. Come late, don't speak, take a plate, and bounce
If I were king for a day, the second thing I'd do after replacing the stars and stripes with a slab of bacon is pardon all the people in prison for "this bitch-ass motherfucker came to the cookout and didn't speak to anyone and then had the audacity to try and leave with a plate"-related shankings.
5. Invite people and not have enough meat
Understandably, there are situations where you made an appropriate amount of meat but your carnivorous friends and family just ate at inappropriate, Fear The Walking Dead-ass levels. But don't be the derelict who invites two dozen people to your crib and expects them to share 10 hot dogs, a stick of beef jerky, and three bowls of grilled beets.
6. Expect people to mind your random-ass food allergies if you didn't explicitly express them
If your weird-ass, "probably should have been weeded out by evolution by now"-ass ass is allergic to ice chips and Cheetos, fine. Tell people ahead of time so they're able to prepare special food for your special ass, or just bring your own special shit. But don't just show up without warning anyone and expect people to be considerate of your "really, really, really, really, really sounds fabricated"-ass food allergies and get mad that you can't eat the meat because you have crunchy food allergies and it was sitting too close to a bag of pretzels.
7. Waste good food
Maybe you let your wretched earth-ass spawn take full plates of lobster salad and hot sausage despite knowing that they won't finish (or even like) it, but it's (somewhat) excusable because they're seven years old. But if you're throwing full plates away at 27 — especially if it's something like Auntie's potato salad or Uncle John's baked beans that are in short supply and desired by other people there — don't be surprised if your bitch-ass ends up in the trash too.
8. Make someone else's man a plate
America is just now recovering from the Great Plate Making Civil War of 2015, where men and women across the land argued, fought, and murdered over whether it was "right" for a woman to make a plate of food for her male significant other. But one thing both sides agree on is that making a plate for your cousin's fiancee is the Memorial Day equivalent of a Panty-Clad "Cousin Faith" from Soul Food teaching Miles how to Dougie.
Basically, don't hand your family member's age-adjacent man a plate unless you want to leave the cookout hand-less.