The angle from which the song is told — first person (I), second person (you), third person (he/she), or experimental perspectives.
Try writing the same situation from three perspectives: as me (I feel), as you (I accuse), as observer (I watch).
Perspective determines how close the listener is. 'I' = intimate, 'you' = confrontational, 'he' = epic.
'You're So Vain' — accusing 'you.' 'Stan' — first verses as 'I' (fan), third as 'I' (Eminem).