Dwelling in one's own subjective experience is typically fruitless. However, paying attention to emotion ("attention is all you need") as a detector of mismatch

Dwelling in one's own subjective experience is typically fruitless. However, paying attention to emotion ("attention is all you need") as a detector of mismatches between reality and expectations is quite useful. But, attending to ones emotional state is only useful if you are willing to update your internal state (beliefs, expectations) and actions to reflect reality more closely.