The big problem with owning a smartphone is that every temptation is just a finger tap away -- ooh, Twitter! -- making it hard to knuckle down on a single task. Earlier this year, Google promised to remedy this with "Focus mode," a new tool that stops you -- ooh, YouTube! -- opening apps that could distract you. You just select which apps like -- ooh, better check Facebook -- you find distracting, and lock them down until you choose to release them.