In Denis Johnson's "Tree of Smoke," the theme of self-reflection emerges through powerful imagery, particularly in the metaphor of staring at one's own face in a cup of bitter karma. This suggests a confrontation with past actions and their consequences, highlighting how personal decisions can reverberate throughout one's life and affect one's identity.

The protagonist's experience represents a moment of reckoning, where he grapples with the weight of his choices. The "bitter karma" implies that the outcomes of life may not always be pleasant, serving as a reminder of the complexities of existence and the inevitability of facing one's truths.