T1 I called by her first name (she was 15 years younger than me) even though she referred to herself as "Dr Lastname". I asked her if first name was OK and she said yes, but she was lying. I didn't care, Dr Lastname was too formal for such an intimate relationship and she needed to loosen up a bit anyway. She was a psychologist. T2 introduced herself as firstname and that's what I call her and she is fine with it. She wouldn't like last name. NEITHER of them (but especially T2) can get the hang of the pronunciation of my name. It's not hard either, sigghhhh