"Killing Time" by John Mayall's Bluesbreakers is a song about longing for someone who is not with you. The lyrics talk about writing letters to this person, asking them to stay with the protagonist and waiting in vain for a response. The protagonist feels trapped in a cycle of loneliness and their days are filled with empty dreams and feelings of imprisonment. The chorus of the song pleads for the person to write back, to tell the protagonist what they want to hear. The protagonist hopes that the person understands how they feel, because "killing time is killing me." The song expresses the frustration of waiting for someone who may not feel the same way, and the pain of being without them. Overall, "Killing Time" is a heartfelt blues song that speaks to the universal experience of wanting someone who is not with us, and the agony of waiting for them to return.