Is it correct to express our emotions to others?

 I have a doubt from long back, that i can express my emotions to others.

NO

 Yes, we can express, but to selective one. I faced a situation in my life, A person 'x' who is called as a good person/calm person/a person with awesome character/.. . but one day he reacted in a different way, within 2mins he expressed 3 types of emotions, then suddenly all started to say that,  he is mentally ill, actually i dono the reasons behind that, why i am telling this??? if everyone express(better not to express) their emotions in a proper way, proper way means, we should have some control in our inner emotions, when someone crossing their emotions and express it as a worry/angry/cries/shouting, there where the problem starts.

'Control, may control problems.'