The most important thing about the stage directions of J.M. Synge's The Playboy of the Western World lies in the dialogue cues. While the typical stage directions are found, describing the set of the play, the dialogue cues prove to play a very large role.
The dialogue cues insure that lines are spoken with certain inflections, attitudes, and mannerisms. Without these directions, lines could be interpreted differently by producers and directors. These alternative interpretations would change the mood and tone of the play.
For example, much of the dialogue is preempted by a "with good humor," "triumphantly," or a "shyly." Without these direct directions, the tone and mood of the lines would change dramatically.