You don't have it quit right I am afraid. I am not sure what exactly you are meaning when you say only some spirits revisit a select few of us. If you are referring to spirits actually materializing infront of a loved one, than yes I agree that this does happen but not as often as people would like and most certainly occurs when the person is not expecting it. I have to state here that I believe all our loved ones (deceased) are around us when we need them, when we want them to be and in truth they see our lives on a daily basis unfold. The fact that we are not aware of this fact is neither here nor there. I am convinced of this fact every single day that I work when those in spirit come through detailing scenarios, conversations, happy and sad occassions for my clients that have unfolded since their loved one's physical passing.
Our deceased loved one's give us signs all the time and we are simply too busy, too distracted, too tunnel visioned to pick up and understand the desired messages they graciously give us. Hollywood and books lead us to believe that messages and signs will come in a very select way. The truth is most signs speak to our hearts internally. They are not normally earth shattering experiences, because spirit works in subtle nuances and grace, not shock value. I tell you this, if we the so called living opened our hearts and souls and shout our mouths and minds off, we would understand and receive far more signs from our loved ones. In order to receive one must believe.