By definition, the focus is a skill that allows people to start a task without procrastination and then keep up their attention and effort until the job is complete. It is an ability to not only pay attention to things that they are engaged in but also avoid distractions that will impede the work they are trying to do.
In fact, the focus is so important to getting anything done that you can’t really think without focus. When you hear about things like perception, memory, learning, reasoning, decision making, and problem-solving, you know that none of these can be done successfully unless you focus.
On the contrary, a wandering mind will make you less effective in your work and your productivity will suffer. The same will also compromise the quality of work giving you less than optimal results. Not to forget that you will also be wasting time every instance your mind drifts off.