In any case the friendships of later life, in contrast with those negotiated before thirty, are apt to be burdened with constraints, reservations, inhibitions. Probably thirty was placing the watershed too late for the age when both parties begin more or less to know (at least think they know) what the other is talking about; as opposed to those earlier friendships – not unlike love affairs, with all sexual element removed – which can exist with scarcely an interest in common, mutual misunderstanding of character and motive all but absolute.

from Hearing Secret Harmonies by Anthony Powell