Luca completely got the point. The problem is livelock.
You KNOW you have something to do, so you are stuck with your laptop hoping that, somehow, the work will be accomplished. Then you try to cherry-pick the highest priority task, but no one has priority high enough to trigger your will to start working on it, no matter how many they are. Then you wait for something, you don’t know what, it could be an email, a chat, telling “you do this NOW!”; almost all your co-workers are nine timezones far away from you so you know it is not going to happen; but you keep switching the windows, you read the RSSs, click on “Get Mail”, read the online newspapers, click on “Get Mail”, and so on and so on.
With a Mac it’s even worse: at your fingertips you have its whole expose-spaces-dashboard-genie-shininess, with active corners and keybindings that make you faster than a pianist playing Bach. So waiting for a deus ex machina you play with your windows, make them turn around, become small small small and then big big big, open and close them, hide them in the Dock, go faster and faster and faster until motion sickness mandates you to stop.
And then you do the only thing left: you write something of zero entropy in the blog. This will be the biggest accomplishment of the day.