I used to multitask a lot more, and a lot more flexibly, when I first started freelancing. Maybe it was because I was doing itty-bitty bits of work, whatever came in that seemed interesting or paid the bills, none of which were very long-form or long-term projects. I also thought that trying to schedule all my client meetings on the same day of the week was 'cause I was lazy to go out everyday, which would feel too much like going to work at a conventional office job.
Now my work schedule swings between the extremes of (a) hermit-like self-imposed isolation at home with the internet on for research but not IMing, and (b) multitasking days for things like meetings, admin work and "grabbing coffee" (see Graham's use of the term). This month it's been mostly (a), which has been great for creative foment, although I have to admit that in this day and age of constant Twitter chatter and link-sharing, it feels counter-intuitive to take a step back and block it all out in order to get anything creative done.
I wonder also if this is why many of my teacher friends are always so frazzled during term time, as I used to be. Preparing a good lesson is "making", but so much of a teacher's life is filled with "managing" --- managing students and colleagues, being managed by bosses and the system. Just as non-freelancers sometimes assume that a freelancer having a "flexible" schedule means they can interrupt his/her day at any time, people in school often assume that a teacher who doesn't have a scheduled lesson is likewise "free" to be interrupted ("free periods" indeed).