Mask means “a cover or partial cover for the face used for disguise” according to Merriam Webster Dictionary. That’s a physical mask definition. I’m going to talk about emotional masks.
We all do have masks. We use depends on occasions. Those are all fine. You don’t need to explain to me or someone else why do you have a mask. That’s good if you are aware of them. You can able to take off when the occasion or situation over.
On the other hand, the ones you do keep them all the time. In the beginning, you did cover some of your weaknesses or parts you didn’t want to show others. Later, you might even forget their existence. Because you are not yourself anymore.