Everybody's talking about designing for delight. Even me! Well, it does get a bit sad when you spend too much time finding bad things in design. So, I went positive. I looked at positive psychology, and behavioral economics, and the science of play, and hedonics, and a whole bunch of other things, and came away from all that with a framework in mind for what I call "happy design." It comes in three flavors: pleasure, flow, and meaning.
I used to think of the framework as being in layers or levels. But it's not like that when you start looking at great digital designs and the great experiences they are part of. Pleasure, flow and meaning end up commingled.
So, I think we need to deconstruct what we mean by "delight." I've tried to do that in a talk that I've been giving, most recently at RefreshPDX (April 2012). Here are the slides. Have a look: