Head in the clouds
Mind-wandering the enemy of focus because if your mind is wondering then by definition, you are not focusing and vice-versa. According to Wikipedia, mind-wandering could be described as the experience of thoughts not remaining on a single topic for a long period of time, particularly when people are engaged in an attention-demanding task. I think having your head in the clouds and mind-wandering is extremely valuable and essential for creative insights. This is because the creative process demands that you first gather information and focus on the problem, then you really concentrate and then let go.
The annals of science, art and mathematics are full of people who came up with incredible solutions when they were just daydreaming - in the shower, driving a car, sitting on a train or bus, walking the dog, etc. And that’s because during mind-wandering we can make connections between remote elements in a new way that has value. Now if we move into the execution phase, where you put the idea to use, then you must go back into focus.