Internal slamming of doors is not as loud, but once these are shut and locked it is an impossible feat for anyone without a key to enter. All you can do if you are the one being shut out is to let the person on the other side of the door know that you are patiently waiting for them to reappear. Loud banging or threats tempt no sane person to let you in.
If you are an internal slammer leave one door cracked for the people who care enough to look for a way in. When you lock others out you are also trapping yourself in place. Better to come out and take the hand offered, or punch the busybody in the kisser than to barricade yourself into a corner for a lifetime.
THINK ABOUT IT
LET IT GROW