#fringe speculation

When do you think Peter realized he had feelings for Olivia?  I think it was waaaaaay before she did for him.  I think it definitely cemented in place in "A New Day in the Old Town", but I think it could be argued that he first realized as far back as the pilot. 

Personally, I'm thinking "The Cure".  He's decided to stay, she shares probably her most traumatic and personal life experience with him, and he decides to put his neck out for her.  Peter Bishop doesn't put his neck out for just anyone!