The Heart is a Lonely Hunter
How we cite our quotes:
Each evening the mute walked alone for hours in the street. [...] His agitation gave way gradually to exhaustion and there was a look about him of deep calm. (1.1.45)
Well that's one way to deal with loneliness. Singer has got it down: if you poop yourself out, you'll feel way too tired to bother with feeling lonesome.
Doctor Copeland jerked the cuff of his sleeve and cleared his throat. His pulse beat too fast and his throat was tight. Sitting in the corner of the room he felt isolated and angry and alone. (2.3.89)
Isolated. Angry. Alone. Yeah, we're gonna let this quote speak for itself.
And the riddle was still in him, so that he could not be tranquil. There was something not natural about it all – something like an ugly joke. When he thought of it he felt uneasy and in some unknown way afraid. [...]
The silence in the room was deep as the night itself. Biff stood transfixed, lost in its meditations. (3.4.14, 16)
Here comes that fear again. Something about being alone is scary to these characters, perhaps because they worry that they might always be alone. And since McCullers has chosen to end the novel with this scene, we can't but think that they totally will be.