The proximity/intimacy that obtains and remains through the lifespan of friendship or connection to people is affected by change in character, virtue, status, habitat, career, personality of each party.
Sometimes, the changes that yank us apart gradually or abruptly from our one time close buddies are inevitable.
The life of every man is like that of a mouse through a maze, sometimes, the mouse navigates a certain path and so never comes in contact with the fellow he started with together, rather, he meets other mice and has to forge relationships with them as far as they are relevant to his course.
It’s a good quality to recognize that those around you at any given time, T in your life are most likely the most important people you have to deal with.
In the end, time and space have a huge impact on our attachment to people.
P.S. – Social media these days causes social dissociation, encouraging relations with the cyberspace more than with concrete identities.