Ghosts are jerks
The Winchesters have lived in the bunker for years now. There was every book that ever existed on things of supernatural nature, there was every weapon that could kill the above mentioned creatures. Sam and Dean have dedicated their lives to hunting these things and saving as many people as they could. Over the years, their beliefs have changed, opened their minds to new things both good and evil. They have changed as people, as brothers, and even more so as hunters. Despite changes, there were always surprises.
It was late in the day, the sun had begun to set. Sam was seated in the main room with his laptop with a stack of books next to it. He heard the entrance door to the bunker open with a creak, followed by a few swears, and finally the door slamming shut. “Dinner's here.” Dean called from the top of the stairs, balancing two pizzas on his arm as he was locking the door with the other.
“You know pizza isn't a food group right, Dean?” Sliding the boxes across the table Dean scoffed and mentioned that Supreme pizzas have vegetables on them. Sam raised an eyebrow and opened one of the boxes despite his complaint.
They had gotten back to the bunker not too long ago from getting rid of a vampire nest a few cities south of where they were. It had been an easy hunt but a long day. “I plan on eating pizza, drinking a beer or two, then falling into my memory foam.” Dean's eyes were already heavy, Sam nodded in agreement.
Dean shut his bedroom door, slipped out of his clothes, and climbed into bed. He turned Netflix on and closed his eyes and sighed. After awhile of auto play, Netflix asked if he was still watching, so there was a few minutes of silence. Before he could select 'Continue watching' he heard loud banging in the kitchen. “Knock it off Sammy!” He yelled hoping his voice would carry to the kitchen. More banging and noise. “Ugh, can't a guy get some sleep for a change?” He asked himself rhetorically, feeling rather annoyed and grumpy at all the noise Sam was making.
He pulled on a random pair of pajama pants and walked down the hallway and into the kitchen. Pots and plates were scattered everywhere, some even smashed on the floor. “What the hell...” He took a few steps backwards and looked out of the corner of his eye into the library. It was trashed. The old books were knocked off their shelves, some even had pages torn out, floating to the ground. “Sammy!” He barked
Sam came stumbling out of his room, rubbing the sleep from his eyes. “What?”
“What do you mean 'what'...open your eyes!” Dean threw out his arms gesturing to the mess throughout the rooms.
“Huh...I thought all that noise was you and Cas.”
“Well it freakin' wasn't. Any idea how the hell all this happened?”
“Ghost?” Sam jokingly suggested.