I had a lady tell me last week, "You've lost weight." And, yes, I had. About 15 pounds. She'd noticed!
Bringing up things we've talked about in prior sessions -- an indication that, out of all the conversations she's had with all the clients, she remembered at least some of ours.
It's never happened, but I think hearing, "I want you to fuck me now," instead of "Do you want to fuck me now?" would be pretty freakin' awesome.
Intra-session contact with the women I consider my surrogate girlfriends is very important. A text or an e-mail can make my day, make that several days (and guess which of my friends-for-an-hour I'm likely to see next?).
Appreciation for gifts. It doesn't have to be effusive, but it's nice if it is.
I enjoy ladies taking the lead, but every now and then, it'd be nice to hear "whatever you want."