I think it’s necessary to control one’s actions regardless how one feels. Certainly when you home alone, you can go around crying if you are upset but it’s a different at work.

I might feel whatever emotions (for example I recently lost loved one so I am grieving) or I might be mad about something but I absolutely couldn’t get all mopey or rage at work. It’s not acceptable in most jobs. If one wants to keep their job and/or professional licenses then they better behave in public or they won’t be able to pay bills

I don’t believe it’s damaging for ones brain or unhealthy. Behaving decently and keep emotions in check in public is common sense. Now when you are at home or amongst family and close friends then it’s a different story (still have to act appropriately but you have more freedom to express emotions)