I like to think of friendship as a sort of quasi-stock market where people represent the individual stocks and their relative cost of investment. Some friendships require a great initial investment of time and effort, and in return they yield a high stream of revenue on a short term basis.
Conversely, other friendships require a lesser initial investment but in doing so relegate themselves to a lower short term profit. The value of these two types of friendships -- when compared side-by-side -- sheds light as to which is the sounder investment.
Though, the first type of friendship provides high initial revenue and a sort of instant gratification, eventually the value of these relationships tends to reach a point of stagnation. Whereas, the later of these two variations experiences a slow but continuous pattern of growth over the course of time. Eventually, the later far succeeds the former, which, in turn, illustrates which of the two investments was the wisest.