People who let their dogs run loose on their campsite, then can’t believe it when their dog charges after us walking by with our dog on a leash.
More than one owner has gotten an earful, and their dog a faceful of pepper spray.
My dog should not have to be harrassed by an off leash dog when walking on a leash. Worse is if my dog tries to run, I will be the one injured.
Yep. I don’t mind when kids “hike” the trails that seem to wander through campsites, but we’ve had kids walk right through where we’re gathered - including recently, with the pandemic going on. (I’m talking about a kid walking between my feet & our fire pit.) This is really a parent issue, but I doubt the parents realize their kids are doing it.
People letting their dogs use close camp sites as their personal bathroom. Saw it this past weekend in our spot before pulling in. Yuck!
Music drives me crazy - any time of day, but especially at night. Even inside RVs we can hear it. Use headphones, people! So rude and selfish.
Somehow I missed this one but everyone has pretty much echoed my pet peeves: people traipsing through our site, dogs off leash, people leaving trash behind, loud parties (and the music that goes with it)! Everyone has their own idea of what is enjoyable about camping but it would be nice if everyone was respectful of others!
we’ve had few bad experiences but no more than experienced anywhere else. One notably peculiar moment was an adjacent camper who made a point to rebuff any forms of social politeness in passing throughout the week did manage to find her voice as we’re packing the boat and camper for imminent departure. She strolled up just as I was dogging down the final boat straps and informed me she’d like me to take her family for a ride around the lake. I impulsively laughed at what could only be a stab at campsite humor but was met with steely eyes suggesting it was a serious demand. I kindly told her I couldn’t and she stormed off without uttering another word. …in hind sight, her brushoffs we’re perhaps merciful.
Loud, self-centered people.
Once, we were camping in North GA. We reserved a spot well away from people in a group spot.
A church group had dropped their gear in the spot next to us.
Not long after, a Scout troop came in and started making a fuss about how the spot the church group was in was actually theirs and proceed to set up camp. The church group showed up a bit later to find the Scout troop in their place.
I went to the ranger station and reported what was going on. The Rangers sorted it out by making the Scouts move to another spot. After that, the Scouts were super loud all of the time. At one point, a kid had 2 plastic soda bottles and was banging them together like Boombas.
I confronted the Scout leaders and they said if we din’t like it, we could leave. I reported this to the Rangers as we went for a hike. Went we got back the Scouts were gone. When we checked out, the Rangers thanked us and said the Scout Troop was banned from the park for a year.
Another time, we were camping in North Alabama. About 2 in the morning, I hear the unmistakable strains of “Free Bird” from a few sites away. I got up and walked over to the site were 5-6 guys, 18-19 years old, were sitting around a fire, truck stereo cranked to 11. I calmly told them to turn off the music or I would call the local sheriff or they could explain to the cops why they were drinking beer in a State park. Didn’t hear a peep the reset of the night.
My ‘pet peeve’…?
People… 
I’m not crazy about people leaving their RV area all lit up, especially when they are inside or asleep.
ATVs and UTVs and the now obsessively popular side by side/2 or 4 seaters! They are loud, kick up dust and blare music as they are racing along trails or or dirt roads or through campgrounds.
I have never actually seen the no alcohol in state parks rule enforced, but I’m glad it’s there’s for situations that warrant it.
All-night spotlights and lanterns in campsites. I understand that they can add safety and be great for kids, but they can also really damper the late-night stargazing. Not usually a problem for dispersed sites, but this can be torture for me when staying over in a campground.
Wet gear or gear that does not dry quickly. 
I hate the feeling of being wet or soggy
Lack of available sites for spontaneous trips when I can finally get a day off. Unless I can go camping during the week, it’s almost mandatory to get reservations 6 months in advance.
Contractor generators. Not the quiet Inverter jobs that sort of disappear into the background after 75 feet or so, but the screaming loud gas suckers that keep everyone awake for several counties away.
Unattended children, or discourteous adults using my campsite as a shortcut. I try to set up to disallow this. I’ve been known to put a clothesline between trees where it looks like shortcuts have been made.
Loud noise during quiet hours.
RVs with aircraft landing light brightness lights left on all night. This happened last time at Garner State park, and 6 tent sites worth of campers proceeded to remove and hide an RVs shore power cord at 2:00 A.M. because of this. And no I was not involved, although I may have instigated somewhat…
People not cleaning up their junk, and messing up camp sites. It doesn’t take long, make sure your camp site is in better shape when you leave than when you arrive.
People that arrive at way too late o clock and make as much noise as possible setting up.
Anyone with a Diesel truck in a campground running after 10:00 P.M., particularly those noisy Cummins engines…
I am sure there are more…
I agree with most of the above; for decades I have used a well set up Jeep CJ or TJ to get where few of the obnoxious “civilized” could annoy me. Although last weekend we could barely hear a generator far in the distance had to listen pretty hard to hear it so not very annoying… the wolves were louder and at least as annoying just before dawn.
…sometimes you gotta take what’s given…
Enjoy!