Enter the half-joke, half-serious concept of “silver springing” someone. It’s the idea that you and all the love you bring with you are unforgettable — like a ghost that will eternally haunt them.

A recent letter from the Boston Housing Authority urged residents of Boston to move out of the city for a better life. The unauthorized letter was sent out as part of an announcement for BHA’s Expanding Choice in Housing Opportunities (ECHO), a program that provides affordable housing to low-income and working families.