Anyway, uh. ^^;; You're right in that if they were closer, he'd feel uncomfortable more often (and I agree about the rest of your assessment; it's not that I think Luna's 'casual' as in flippant, but she's casual as in she speaks plainly which can sort of put Harry at ease and not at the same time), but at the same time I think they have a weird connection in terms of their history, so if and when they're talking about that, he's comforted rather than uncomfortable. I can see what you mean about 'pushing buttons', though he seems to avoid dealing with it entirely rather than overreacting like with Draco.