Time and distance are not important between friends. When Friend are in the Heart, they remain there forever. You may be busy but trust me you are always remembered.
As I saw ants crawl up the wall, I noticed that no matter how busy they are, they still stop and communicate with each other. I hope we can be like them.
People never know how special someone is until they leave, but maybe sometimes its important to leave, so they are given that chance to see how special that someone really is.