I find it psychologically very different knowing that anyone can talk to you (and you can't ignore like if you were online) and see you. It forces me into a "work mode" psychology.
If you're highly creative, self-discipline is often at odds with the way you work/think. Unfortunately, many office drones are not creative and have no concept of this. Some expect developers and IT people to punch a clock and start typing code until close of business day.