I don't disagree with its use per se, I just think it's horribly inefficient for people to do it. There is a cost to switching focus. Please note, I am complet

I don't disagree with its use per se, I just think it's horribly inefficient for people to do it. There is a cost to switching focus. Please note, I am completely unqualified to make this observation, being only a software engineer, but it seems to hold true in my own life, so... There are tasks which can be done simultaneously, due to the fact that they use different parts of the brain. Starting at a low level, e.g. breathing and driving a car; changing gears while steering your car; listening (and paying attention to) a radio program while driving; etc. But this gets inefficient when the tasks start to overlap cognitively, e.g. talking on the phone while driving (which is why it's unsafe to do those two things at the same time -- has almost nothing to do with hands-free vs handheld IMO). I'm not saying you shouldn't context switch. I'm not saying you shouldn't do two things in parallel. I'm only saying that you should know the cost.