Mike Monteiro:
In my experience, most people don’t schedule their work. They schedule the interruptions that prevent their work from happening. […]
People rarely schedule working time. And when they do it’s viewed as second-tier time. It’s interruptible. Meetings trump working time. Why?
The other problem is that for so many corporate and team environments, the schedule for makers is run by managers. A manager gets things done by checking off their to-do list 15 minutes at a time. A maker, however, gets things done by working on something that doesn’t fit on a to-do list, and they need a good 4 hours of uninterrupted time (preferably one or two of those each day for a week or two).
See also Paul Graham’s article, Makers Schedule, Manager’s Schedule.