If you are focussed, you put your mind on one job and keep it there, as if you have decided you will not be pulled away. A focussed student sits down to study and does not keep checking a phone; a focussed team knows what it is trying to win. Used this way, the word is praise: it says you are determined, not merely quiet. You can also stay focussed, meaning you keep going when it would be easy to wander. Though actually, the two-s spelling is the British one. American English writes focused with one s, and that is what most Taiwan textbooks and apps use. Same word, same meaning; the extra s is only a spelling habit, like travelled against traveled.