Focus means fixated (thinking) about one thing while filtering out distractions, to fulfill your potential you ought to cultivate the habit of being focused, in abundance and in the proper balance because failure to focus will leave you without a sense of direction, clueless and blindsided.
Being focused directs you, makes you strive to become better than you are, makes you elevated and has the potential to take you to actualizing your dreams, it doesn't come naturally to us but it is essential for everyone who want to maximize potential to cultivate one.
You can gain tremendous power, discover your strength, gives you ability to gain direction and intentionality which will eventually yield results, even you don't accomplish what you desire or others dont step aside for you, you can't be focused and remain unaffected by it, because without focus you can end up drained, miss every opportunity that comes along and in the long run end up unable to achieve much.
It takes lots of effort to stay focused since people don't naturally remain focused (we are not robots) there are lots of things battling for persons attention - not enough time, not enough resources, not enough help culminating into problems, setbacks, shortcomings and distractions giving us reason for not doing what we ought to do but these shouldn't stop us, because gaining the ability to focus and stay focused has its significant payoff (bringing out the best in you, maximizing your potential, abilities and eventually leading you to achieve success).
It might seem a huge task with present life circumstances as everyone is being pulled in many directions with lots of choices and opportunities exposed to us, making us spend much of our time, energy and resources on a little bit of this there and here at every moment, in turn we achieve little or nothing, the only way to deal with this challenge is FOCUS, with focus comes concentration which will aids in pulling our energies to a single point in a specific direction. If you lack focus, you will be attempting everything and anything, you will be all over the place, this will suck the life out of you, sap up your energy, kill off your dreams and opportunities, yes you will be busy filled with lots of motion but no direction and in the end you achieve nothing.
Something wonderful happens when we narrow our focus and set goals, the mind doesn't reach towards achievement until it has a clear objective. That is where the real magic starts.