I don't think it's just recognizing him. Anything that he sees take notice of him.
That would explain the bird and the cat. He saw them looking.
People walking by that don't spare him a second thought aren't affected. People who notice him without being seen aren't affected.
Not sure what's up with Daidai at the end though.
HELL yeah we love smart protags. I personally love the gloomy girl, she's smart in her own her, calling out the fact that everyone else is behaving even weirder than her. I love characters like that, reminds me of Junji Ito's Army of One