Have you ever thought why people come into our lives, then leave, and then return again

I often wonder why people come into our lives and then leave. Then as time passes, they return months or years later. Is there something on this journey of returning  friends? Many of us are intutitive although, we do not use this ability. Have you ever felt skeptical about the return or wondered if you did something wrong? There actually is a spiritual reason that many of us have not looked at. The answer will amaze many.