Which details in the description of the stranger create a sense of his agitation or distress?

In Joyce Carol Oates’s short story “Where is Here?” the stranger appears to be both excited and anxious about being inside his childhood home.
Oates shows that the stranger is in some type of distress through her descriptions of him. When he first enters the house, the text says that “his eyes darted about the kitchen almost like eyes out of control. He stood in an odd stiff posture, hands gripping the lapels of his suit as if he meant to crush them.” This suggests his body language is tense and uncomfortable, which indicates his mental or emotional stress.
Later, when the stranger enters the living room, he “[with] fastidious slowness . . . turned on his heel, blinking, and frowning, and tugging at his lower lip in a rough gesture that must have hurt.” This describes his exacting attention to detail while demonstrating his clear nervousness via awkward physical gestures.
The most poignant example of Oates's descriptions, however, comes when the stranger sits in the window seat. In a “slow, dazed voice,” the stranger mutters about the increasingly bizarre and existential riddles his mother used to ask him while they sat in the window seat together. The riddles themselves are odd enough, but his talking to himself aloud suggests he is in his own world, consumed with visions of his past—which might indicate that his purpose for visiting his childhood home is a complicated mix of both positive and negative factors.
As the story progresses, the reader realizes the stranger’s nervous emotional state because of Oates’s careful descriptions.