Yes, but of course Snape went about it in such a ham-handed fashion. It's extraordinary that he is such a good spy and yet somehow so bad at reading many people (at least the ones against whom he is prejudiced) and at knowing how to act around them sometimes in order to achieve what he wants. In your mind, is this because there is such a difference between how Death Eaters and most of his Slytherins think and act, and how most Gryffindors do? Or is this mainly because he has had such a long-standing chip on his shoulder over said Gryffindors?