What is the significance of half step notes in music theory and how do they affect the overall sound of a musical composition?

In Music Theory, half step notes are important because they create tension and movement in a composition. They are the smallest interval between two notes in Western music, and their use can create dissonance or resolution, adding depth and emotion to the music. Half steps can create a sense of urgency or drama, and their careful placement can greatly impact the overall sound and feel of a musical piece.