When you watch one of your favourite moves and that favourite scene comes on and after you think to yourself “I wonder what makes me like that scene so much” if you end up looking into the scene and continue to rewatch it and 9/10 times its the score behind the scene.
For this example I will use an action scene from a movie like the lord of the rings when are main protagonist are running away from an army of Orks we as the watchers feel afraid or at the edge of are seats and the driving force of that is the intense instrumentals in the background blasting on as they run down a hill to the clearing in the forest we feel scared for them we know how they feel just by hearing the instrumentals if you change the instrumental to something less epic and exiting then it would feel out of place and stupid like the mission impossible theme or the benny hill theme song
A scene can be ruined if the song doesn’t fit the feel of the film or the scene like action movie with a romantic soundtrack most films go on with what the score feels like to the director or writer.