Messy
Sam was not a neat person; in fact, his room was the most untidy in the entire base. This fact often led to discussions about how the hell he ever managed to find anything in there.
The mess drove the scared-of-dirt, Sunstreaker absolutely nuts, to the point where he refused to enter the room in his holo-form like all of the other Bots.
Sam hadn't realized it was possible for aliens to suffer from Obsessive Compulsive Disorder, but he found it damn funny.