Is there something you do when you're ready to get down to business? Do you stick your tongue out when you're concentrating or sit in your chair differently?
I noticed today that when I'm ready to really get some work done on the computer, I kick my shoes off and sit cross legged in my chair (no, I don't fall out, yes, at least one foot usually goes to sleep).
First I quit posting. Then I sit on the edge of my chair. I don't know why it's a subconscience thing I do. I don't start on the edge but I end up there.