Harry potter and the deathly hallows

Over the course of the book you really grow to dislike snape he's sort of the bad guy innour mind someon emit to be trusted by us because Harry believes he is bad to the bone. But what I don't understand is how even though Harry thinks he's a bad person how is it snape still tried to save Harry throughout half the book but only some of his accomplishments were mentioned even though they had a major impact on what happened in the future of the Harry potter series. Snape in peoples eyes are that he hates Harry believes he goingnto end up exactly a his fathr and also that he relishes his fame for being the boy who lived. Harry hates him and lupin said he dis only because Harrys father hated him and that he's resuming an old grudge. But realy snape is a good guy who's been trying to save Harry keep him safe and to keep him from harm so that he doesn't get hurt. After we learned this we still believe the only reason snape hasn't killed Harry was because he was ordered by dumbledore to protect him and not to let anyharm befall him. But really snape would havenprotected Harry on his own accords in my belief he would have did it because he knows it's something lily would have wanted him to do to protect her son so that he doesn't get kille or hurt by voldermort or the death eaters. Anapenis really a good guy but not everyone ruly believes that. I wonder if dumbledore hadn't ordered snape to watch after harry would snape have watched over him anyway because ofnlilly and her snaring him to do that or left him to be killed one of the 6 other hrs as voldemort tried to or just let him die and not cared about what happened