Use both efficiently.
Focus, as we traditionally define it, is doing one task or project, while minimizing time and attention on anything else. It is maintaining a singular point of attention when the brain concentrates its abilities in the prefrontal cortex, ignoring all extraneous information. It is in this state of flow, when high-quality material progress happens the fastest, that the importance of focus is incredibly important and often preached by business leaders.
The opposite of focused is not unfocused. To be unfocused is to be distracted (checking social media, reading blogs aimlessly, etc). It is merely a state of inefficiency or waste.
There is a complementary state to a focused mind known as the diffused mind. This is when we make progress by obtaining a subtle, but equally important, clarity of mind. Diffuse thinking happens when you let your mind wander freely, making connections at random. The diffuse mode of thinking does not happen in any one area of the brain, but rather all over.
The challenge for all is to cultivate an efficient state of mind, depending on what we wish to accomplish.
Recognize when you are a in a focused mindset and build habits to reduce distraction (tell people you’re going off slack for a while, turn off text messages, close chrome, book a conference room, etc). Likewise, determine what helps you get in the diffused state (music, whiteboards, early mornings, etc).