When you have to start something at a certain time, your brain starts doing all the work of figuring out when you have to stop doing whatever you were doing before, based on how long the changeover will happen. So if I have to be at work at 8:00 AM, that doesn’t mean I can set my alarm for 7:59. The process of changing from “asleep, in my bed” to “at work, ready to be productive” involves plenty of steps, and it’s part of my job to figure out how long those steps take.
But this is true for pretty much everything. If I want to go to dinner with my friend at 6, I need to know the changeover process from “watching a movie,” or else I won’t get to finish it (or I’ll be late to dinner). This whole thing is why people get stuck in that loop where they have an appointment at 4 PM, so the whole day is shot; they can’t properly assess what a novel, unique changeover process looks like. And especially if you’re trying to do multiple things, then for each thing, your brain is re-doing the changeover calculations.
Deep work helps! It’s easier on the brain to do 1 thing for 8 hours than to try to do 5 different things in that same time period. You’ll lose a lot of time to the changes themselves, and your brain will have to run this whole subroutine to move from one to the other.
Deep work, routines, and acceptance of lost hours when they happen – these are the ingredients to a low-stress day!