People I don't understand: Motionless telephone talkers

I don't understand anyone who sits still while talking on the phone.

I don't speak to people on the phone often, but when I do, you can bet that while I'm talking, I'm also emptying a dishwasher, sweeping the kitchen floor, folding laundry, or doing any number of mindless chores in need of completion.  

I can't imagine why anyone would just sit there and talk. It's like they're trying to be unproductive.