I watched a couple of really bad directors work, and I saw how they completely botched it up and missed the visual opportunities of the scene when we had put things in front of them as opportunities. Set pieces, props and so on.
One friend in a lifetime is much; two are many; three are hardly possible. Friendship needs a certain parallelism of life, a community of thought, a rivalry of aim.
There's no subtext in Harry Potter really; it's all magic, anything can happen. Why do I say this? Because it's a magic spell. It's quite nice in a way. There is a real freedom to it.