Renfield: "Do you mind if I sit in that chair? That's the chair I always sit in."
Cassandra: "Yes I do mind. I'm having a nervous breakdown."
Renfield: "I don't think you've been taking your medicine".
Cassandra: "I don't take medicine. I'm the nurse." ...
Renfield: "Well, maybe you should start taking it, because you don't look very well. And you're still sitting in my chair."