you never gave us the play...
In his comedy "Poor Harold", Floyd Dell presents in a one act play depicts the adversity of Harold who wrote letters to a married woman without knowing that she was fond of having affairs despite being married.
In this excerpt from "Poor Harold.” the author represents all the bitterness, shame and some sort of resentment Harold has in his heart. By reading sentences like : "how was I to know that a rather plain-featured woman I sat next to...was conducting a dozen love-affairs?" we can see that Poor Harold is fulled with bitterness.
So the final Answer is:
Bitterness
I believe the tone is somewhat dramatic based on the dialogue such as "shot his hand out in front of him", it makes the story seem a lot more interesting than what it really is; a normal encounter.