Quick: why do you own a cell phone? Is it to play Candy Crush or Angry Birds? Is it to update your Facebook profile with the proud news that your theatrically gifted seven-year-old has been cast as the third tree from the left in the school’s production of the Wizard of Oz? Is it to peek at football game scores during the interminable condo association meeting? It might be for all of these things, but it’s primarily for convenience. If you’re old enough to remember a life before mobile phones, you’ll recall that making calls while on the go involved finding a phone booth and a quarter and pretending not to notice the highly questionable substance sticking your shoes to the floor.