Sometimes we feel a bit of pain over things missing from our lives:
gifts, childhood toys, that old silverware, memories...
But there is a special kind of pain, a person feels over people missing from their lives.
There is a trick; it is not this simple, see.
The trick is this: Often, it is only when that person begins to come back into our lives, that we realize just how great, acute, that pain was, and is, and this mutes the happiness one would fully feel at the reconnect.