Single File by Elliott Smith delves into themes of isolation, disillusionment, and the struggles of personal identity. The song explores the feelings of being an outsider and coping with societal pressures, emphasizing a sense of melancholy and introspection. The lyrics paint a picture of navigating life without clear direction, metaphorically walking in a 'single file' line, suggesting conformity and the struggle to break free from it. Smith's poignant moments include his reflective expressions on loneliness and the search for meaning within a constrained existence.