Friendship

The beauty of a real friendship is it doesn't need to be defined by anything else; coworker, colleague, love, family, regulars, etc. Sure, these are good starting points for a friendship, but in many cases the friendship falls apart once the initial association dissolves. You say you will, but will you REALLY keep in touch with coworkers after leaving a job? Will you REALLY stay friends with an ex? Will you REALLY keep in touch with other fellow students once you graduate?

The separation between the initial associations (coworker, colleague, family, love interest) and an actual friend is subtle. There is no real point of comparison between a friend and a temporary acquaintance; one can spend and enjoy time with both, one can confide in both, one can truly believe they can keep this person as a part of their life in both instances until they realize they can't.

Viewed this way, relationships are like Schrödinger's cat, simultaneously alive and dead until it is revealed the person is not a "true" friend. It is only during moments of appreciation (possibly separated by days, months, even years) where the cat is revealed to genuinely be alive.