Diligence
Compared to other virtues (Wisdom, Patience, Courage, etc.), I would say it is non-essential But it is definitely a non-negligible, and very practical, down-to-earth virtue which has potential to outdo all the other virtues in terms of worldliness Basically the very virtue which so-called successful people owe their success to (Passion, Never-Giving-Up, etc.) (I don't praise it too much. It is still non-essential. I'm just shedding light on it.)