some of my players in my PbP game don't check in *looks at bhu*
I can second this
Mostly though, it's the fact I yo-yo between highly excited about something (Witness the homebrew production when I first showed back up), and burning out. And currently I'm right on the edge of the latter. Which longtime residents will remember for causing me to have a five year absence from the boards the last time it hit hard.
And there's always something else to turn to creatively (I write short stories and novels, for example), so I wander off and do that instead. Which, admittedly, I need to do anyway, I'm just avoiding for reasons that don't have anything to do with D&D.