As mentioned, I tend to procrastinate. It's not deliberate by any means... well, ok, sometimes it is because I just don't want to get started or finished or even be in the middle of whatever it is I am working on. Other times it's a question of having other things that I deem to be more important to work on - which can translate to "anything is more important than this is." And sometimes it's just because I have an insatiable sense of curiosity and go wandering off chasing down tangents and random thoughts.
Actually, that's a lot of the times, come to think of it. I have a tendency once I discover something new, especially if it's interesting or has the potential to contain lots of useless but otherwise fun knowledge. I confess to being something of a trivia junkie. Actually it goes beyond mere trivia into the arcane, esoteric, and downright utterly and completely useless for ninety percent of anything, yet still addictive. I can't even reasonably claim it's "research" for any particular story, because there is so much of it out there that I have taken the time to read about and/or look into that even if I was a prolific author I won't live long enough to make use of them all.
Of course, from time to time something I learn does wind its way into something I'm working on. There are also the odd ideas and plot lines or other story details that might be suggested. Mostly they tend to work into my stories in terms of the little details, nothing major, but those odd little bits that ground a work in the reader's imagination and makes the fantastical elements I'm weaving that much more real for my audience. Which only makes it worse, because then there is the little voice in the back of my head that says "you know, this *might* be useful someday" and so I keep going.
Mostly though it's about the desire to chase those tangents. To find out where something interesting leads, follow the threads (without unraveling them), and generally stuff my brain with a thousand more essentially useless tidbits. All because it's fun.