Good point there about the 'Heart on the sleeve" Voilet High!
Hrmmm, so what would Snape class as showing emotion...
I'd say definately whatever made him change sides... I cant' see him changing to DD's side due to something he got angry with Voldie about. More likely that he a)started feeling sorry for someone or some people, b)wanted to protect someone he cared about c)couldnt' hack the killing anymore? (okies, gettting desperate here!!!)
And if the first one is (like I guess) about rejection from Lily, then that would be having people see that he cared about someone other than himself (not avery slytherin/DE thing to do!) (Oh, no offence to Slytherin)
So, for a potential third.... Hrmmmm.... wonder if he's ever cried about anything??? POssibly a bad school result, that really got to him, and due to stress, waterworks??? (okies, getting desperate I know!!! )