Distance play a huge role. I have friends in school then that we can't do anything without each other. Some months after school when everyone have traveled, the communication diminished drastically.
There is a particular friend of mine that we are always together 24/7. If you see me in a particular place and you don't see her, just look around you'd see her close by. But now it is not the same anymore.
DISTANCE.... is the culprit lol