After Opening the Door, I Went to a Different University

There is a locked door in everyone's heart. Some people's doors are closed and have never been opened in their entire lives; some people's doors are open and there is no obstruction inside and outside. The door may be dilapidated, or it may be magnificent. This door is our deepest secret and boundary. It is both a shelter to protect treasures and a cage to imprison the past. There are different opinions about the truth behind the door - some say it is the other side of fantasy and the memories of loved ones, some say it is the past and pain that they do not want to touch in this life; some even say that behind the door is connected to an alien civilization, or a trap of Satan lurks. All speculations point to the same end point: true exploration does not lie in finding new horizons, but in mustering up the courage to examine one's own heart. Welcome to this world built by "choice" and "unknown". What's hidden behind your door?