The phrase "I see only my greatest hits" in this context means that the speaker, when reflecting on their life or memories, can only recall the most significant and memorable moments or achievements. It suggests that when they think about their past, they focus on the highlights or the moments they consider the most important or impactful. These "greatest hits" are the moments that they want to remember and be remembered for because they hold special significance and meaning in their life. It's a metaphorical way of saying that certain moments stand out and define one's life, and those moments are the ones that continue to hold significance even after they have passed.