In your opinion, what did Snape feel/think when he saw Harry's memories, in book 5?

I don't think he felt something special... I mean, yeah now we know that he was working for Dambledore and he was actually taking care of Harry, but he was doing all these just for Lilly. So, probably, he didn't felt anything, he was just concetrating on the job he was given, train Harry.

I think he hid his feelings. I think he had to realize how Harry felt on so much and Snape was good. So to see and feel all of the love,hate, anguish, and fear...it had to have effected him some way.