I was one of the original crew of the USS Tarawa, LHA-1, our duty was to transport marines to their amphibious assault. The ship was brand new, no bugs, no rodents. We sailed her from Pascagoula Mississippi to San Diego through the canal with just the 237 man crew, no marines.
We took exceptional care of the ship. It was our home. There was NO food in berthing areas, no trash anywhere, ever.
Then we picked up 5000 marines and housed them for 30 days at sea until they did their practice assault on Camp Pendleton (we wanted to assault/capture Tijuana for a day but noooooo).
They trashed the ship. litter and apple cores everywhere, candy bar wrappers, half eaten junk food stuffed into cubby holes. Not to mention smoking dope on a fueling station right after a refuel, lighting up while standing in 2" deep fuel. They acted like they just didn't GAF.
Their offload was glorious. The Tarawa was a round bottomed carrier so she could operate in shallow waters. When not under power, she turned sideways to the swells and rocked like crazy. The Marines weren't used to our brand of rock and roll and they were adding USMC puke to their mess in buckets. Then they climbed the boarding rope ladders into the landing craft and sat awaiting orders to the beach for a couple hours. They were packed in like sardines, puking all over each other. The few who weren't sea sick were soon puking anyway. Good riddance.
The ship's crew took the opportunity to man the rail and add to their misery with streams of warm sailor pee. What were they going to do, they had a date on the beach. We had another week to do at sea and every day of it was spent cleaning up for marines and throwing their adrift gear over the side.