Sam looked around the bunker. He tried to find what his brother had been seeing in this place, but it just didn't feel like a home. Sam had homes, his first home that he could remember was in Stanford, a dorm he shared with a Architect Major. Then it was a two story apartment just off of Campus once he got a good enough paying job as a waiter and bartender at a restaurant/bar. Those places were nice and Sam was still stunned that he had a couch and bed that didn't have anonymous stains and smells. He had a place that he could comeback too and fill with his own anything, because those two rooms were his own to do as he wishes. Unless it was said not to do in his renter's contract.
His next home was when he and Jessica got a place, because their relationship was getting serious. It was bigger, with a proper kitchen and living room. He had a home he shared. It was stable and nice and there always. He had a bed with memory foam that was soft and he and Jessica slept in it together.
Then Dean came and Jessica burned on the ceiling, and Sam was back on the road with motels and motels and motels and no home. Then Dean went to Purgatory, and Sam was in a motel.
But this motel was different, he started a new life, and made it his home, and ran over a dog. He met a vet, and they bought a home together. They were happy, Sam was happy. Sam forgot about hunting and his brother, but that was ok, because he had a new life, a new home, a new family.
Her husband was alive, and he was back in a motel. Dean was alive and he was back in multiple motels.
And now he was in this bunker, this cold heartless bunker with no signs of sunshine and windows. No light, no fresh air, all cement and grey slabs of wall. The beds, even though they were memory foam, they weren't soft like the one he shared with Jessica. Even though this was a base to come back too, it didn't feel like a home, at least none that Sam had. How could Dean think this was the best? Surely Dean could compare this to his homes and find flaws in this bunker.
"I haven't had my own room in like, ever." Dean's voice reverberated back into Sam's thoughts, as he glanced around his brother's decorated room with guns on the wall and pictures without frames leaning against things to stay upright.
Sam looked at Dean and realized, this was Dean's first home. Of course the one before their mom had been tainted by the fire.
Of course Dean had a home with Lisa and Ben, but it wasn't his. Sam knew how his brother was, probably doing chores and work to accommodate his stay, sure maybe at the end he felt more like he belonged, but Lisa probably didn't know how you had to beat the ideas into Dean that he was actually apart of something good.
So maybe Dean was mesmerized by the lack of stains and odd smells; the soft beds; and four walls he could do what ever he wanted to with. Maybe Dean was thirty-three, just now learning the stability of having something to come back too. Sam wasn't the one who was going to rip that away from his brother, just because he's had the experience of knowing what homes are like before they got the Bunker.