Naming what you are feeling is a standard instruction in mindfulness and in several therapies. The effect is reasonably well documented and does not depend on the name being correct.
Language changes the processing
Describing an emotional state in words engages a different mode of handling it than experiencing it wordlessly, and studies of affect labeling find reduced intensity when people name what they feel.
The effect appears even when labeling is not intended as regulation, which suggests it follows from the act of description itself.
This is part of why writing about a difficult experience is often reported as helpful, independent of who reads it.
Specificity carries more of the effect
Broad labels like bad or stressed provide little to work with, while a more specific term identifies what the state is about.
Distinguishing disappointment from resentment or apprehension points toward different situations and different responses, which is information the broad label discards.
People who habitually describe their states in finer detail appear to manage them somewhat better, which is the basis for teaching vocabulary as a skill.
Observation differs from identification
Mindfulness instruction frames the label as a description of a passing event rather than a statement about the self, hence noticing anger rather than being angry.
The distinction preserves a small separation between the observer and the state, which is what makes the state feel less total.
It also implies impermanence, since something observed arriving can be observed leaving, whereas an identity does not obviously do either.
The practice has failure modes
Labeling can become analysis, and extended examination of why a feeling is present is closer to rumination than to noticing.
The instruction is deliberately brief for this reason: a word or short phrase, then a return of attention elsewhere.
Used as a way to argue with or dismiss a feeling, it becomes suppression, which behaves differently and generally works less well.
Where it fits among other tools
Labeling addresses the intensity of a reaction rather than the situation producing it, and it does not replace changing circumstances that need changing.
Its usefulness lies in creating enough room to decide what to do next, particularly when a reaction would otherwise drive the response.
For emotions that are persistent, overwhelming or connected to trauma, working with a licensed therapist is the appropriate route rather than self-directed practice alone.