here where I live and work when a person shows inappropriate emotions or is unable to show emotions it is called lack of affect, self regulation, shock, PTSD nervous habit, anxiety, depression, agnosia and many other terms too depending upon the situation and other accompanying symptoms.

for some people its normal for others its a learned behavior for others its a physical or mental health problem.

I have done it before.....with in me it was called depression, grief, stress and anxiety. the treatment for me was antidepressants and antianxiety medications.....

yes it can be annoying. your treatment providers can help you learn why you do it and how to control/show your emotions appropriately.