That old devil dialogue

In my writing stint today, I wrote a lot of dialogue. I like writing dialogue, and I think I'm good at it (please, don't disillusion me!), but I always worry when I find I've written a number of dialogue-heavy pages. Is dialogue the easy way out? Am I cheating the reader of dense, informative, deep-delving narrative if I write a lot of spritely, fast-moving dialogue? I try to deal with these doubts by shelving them--much better to think about that later, when I've actually written a draft.
I worry though that I 've made some kind of moral equation: dialogue = lightness, triviality, speed; narrative = gravity, significance, slowness. After all, is Muriel Spark (dialoguist extraordinaire) a lesser writer than John Updike (the king of adjective-laden narrative)? I don't think so. And while we're there, I'd like to say that Muriel's book Memento Mori is one of my favorite books, and much funnier than you'd think a book about aging people and death could be.
I'm reading Bird, by Angela Johnson, a writer from Kent, Ohio, and a MacArthur winner. It's both light and grave, and so far a wonderful book altogether.
Note above another picture of my incredibly messy office.