We cross our bridges when we come to them and burn them behind us, with nothing to show for our progress except a memory of the smell of smoke, and a presumption that once our eyes watered.

The line compresses several familiar proverbs—“we’ll cross that bridge when we come to it” and “don’t burn your bridges”—into a bleak, ironic image of human forward motion. It suggests that we often deal with problems only at the moment they become unavoidable, and then, having passed through them, we destroy the very means of return. What remains is not tangible achievement but only sensory residue (“the smell of smoke”) and a self-justifying story about suffering (“a presumption that once our eyes watered”). The tone implies skepticism about narratives of progress: movement through life can be irreversible and self-sabotaging, leaving memory and rationalization in place of real gain.