In my short career as a researcher-writer, I've always done my work at home, or at coffee shops, with varying degrees of productivity. Each offers something (convenience and sociability, respectively), but both offer their share of distractions. But pros and cons aside, the fact is that I've never been an office worker, because I've never had my own office. I shared with two other TAs as a grad student; as a faculty member, I share an office with a lecturer. And no matter how great your office partners are (and mine have been invariably good), you cannot treat a shared office as a work space. Add to that the hustle and bustle of instructional activity, and you might as well give it up.
Now, for the first time, I have my own office: a glorious, attractively-painted, freshly-carpeted twelve-by-twelve space with lots of sunlight, in a building for researchers (that is, no classrooms, no office hours). The difference is amazing: I come to work, and I'm "at work." No one comes by to ask me about whether I've filled out some sort of paperwork or other. Nobody is standing in the hall, chattering on a cell phone. Just me, in my sunny corner office, reading and writing. It's a real work space, with no distractions (unless I really go looking for them -- and sometimes I do).
I now officially have no excuses.