As I walked into a musty theater in my hometown to finally watch Avatar: The Way of Water, I found myself swimming through a strange array of emotions and stray thoughts. There was some child-like excitement, some curiosity, and at least one question that somehow only occurred to me as I took my seat in a crackled pleather chair: Er, should I have rewatched the first one? The one I haven’t watched since 2009 and remember next...