What does it mean?

Now I'm left in a state of endless thought as usual. Y'know, everyone knows that people come in and leave out of ones lives constantly. It happens every day. Everyone has their purpose in our lives, weather it be brief or continuous. Naturally, many people (not all) eventually leave ones life because they have served they're purpose for us, and us for them. However, what does it mean......if a person that left ones life, pulls a Brett Favre. You thought they were gone, they said they were gone, but yet here they are again as if they never left. What does that MEAN!? Have that same person be called for a new purpose in ones life? Has their purpose in ones life not been fulfilled? Where they never even gone at all, just dormant in your life? Now I'm left in a state of endless thought..........as usual.