Sam doesn’t decorate his walls because Jess was an artist and she used to decorate their walls with her original art. Sam just doesn’t feel right hanging anything on his walls, because what if something happens and he has to leave it all behind? His space is utilitarian because all it needs to do is provide him with a place to sleep and change clothes.
Sam does, however, have a special box under his bed, almost like a hope chest. It’s about the size of a cigar box and he keeps things from cases or people he’s met. Inside this box are some of Dean’s old jewelry, one of Bobby’s trucker hats, a charm bracelet Madison wore, ticket stubs from a movie he and Jess went to (they were still in his jeans when their place burnt down and it was just luck he still had them) the ugliest postcard he’s ever seen (Arizona if you’re curious), and a menu from the best bar and grill Sam and Dean ever visited (New Jersey, believe it or not). This box goes in the bottom of his duffle bag every single time he and Dean go on a hunt because he never knows if he’ll be able to go back to the bunker, but he’s got his most precious possessions with him everywhere.

