My motto in life has always been to treat others as I would hope to be treated, and apply that to WGs as anyone else. Make it obvious to a WG that you couldn't care less about her and you are likely to be treated the same in return.
This was brought home to me early on in my punting career when an outcall girl admitted that she felt uncomfortable with clients who wanted to get straight into the action without any kind of buildup. For the price of a cup of tea and a chat, I had a very passionate session that went long over time, that I very much doubt I would have had if I had insisted we get straight into it.
Over my punting career, I have had many extras, such as being offered services for free that would usually be charged for, extended unpaid time, had meals cooked for me, even free overnighters. Of course, there are those who will say that there is no point in being friendly because being friendly doesn't guarantee you any extras. That is probably true if you are only interested in a pump and dump. And they are right that there is no guarantee. However, the opposite is surely true, if you are not friendly then you are guaranteed not to get anything extra. I also suspect that if you are only being friendly in the hope of getting something extra that you will be seen through.
There is no reason why a WG can't be a friend, anymore than you can be friends with anyone else you meet. But the important point to remember is that if she is charging you to see her, then you are client first and friend second. And be especially wary of those WGs who would seek to exploit your friendship. I don't ask for anything in return for my friendship, and I don't expect to be asked for anything in return.