"I think it's the joy of discovery," Severus replied quietly. "This is still so new for both of us." He found his gaze wandering, cataloguing Al's features: his bright eyes, the slight, wondering, endearing smile. "I've had... two friends in my whole life before I came here, and I lost them both. My childhood was certainly no bed of roses: no siblings, no money, my parents constantly at war.
What we have," he sighed, "is utterly outside my experience, in that life or this." A wry, fond smile. "Certainly not something I'd ever call 'common'."