Multitasking provides the illusion of productivity. Even though I know that I get more done when I focus on one thing at a time, I often find myself in denial. Subconsciously, I equate being busy with being important; and, the best way to show that I'm busy is to show that I need to multitask to get everything done.
This presents itself in innocuous ways like reading and eating at the same time, or browsing the internet while waiting in line. But on occasion, I find myself splitting attention between email and an in-person meeting.
It's unsettling that I do this instinctively and only catch myself after my phone is in my hand. But, since I was able to condition myself to do this in the first place, then I suppose should also be able to condition myself to stop.