Window and Mirror
I don't remember where I read this, but the story goes like this:
A depressed man went to meet a rabbi, in search for help. The rabbi took him by the hand and led him to the window.
"What do you see?"
"I see people... Men, women and children."
The rabbi then took the man in front of a mirror.
"What do you see now?"
"I see myself."
"Exactly. You need to understand that both the window and the mirror are made of glass, but the glass in the mirror is covered with silver on one side. When you stop seeing other people and only look at yourself, the glass turns into a mirror and you cannot see far anymore."