Final answer:
The subject of the question is Life Skills, discussing missed opportunities and taking action to pursue one's dreams and goals.
Step-by-step explanation:
The subject of the question is Life Skills. The question discusses missed opportunities and the feeling of letting one's life slip by. It emphasizes the importance of making choices and taking action to pursue one's dreams and goals. It also mentions the concept of the road not taken and how our lives are influenced by the choices we make and the paths we don't choose.