I agree. For me it depends on what I'm in the mood for. There are times when I simply want a therapeutic massage and nothing else. If a masseur offered one, it would depend on how 'into' the happy ending I felt he was. If we had clicked during the massage either by conversation or by a mutual interest, and he showed a genuine desire to provide one, then perhaps I would allow it, but if he offered and I felt that he was going to provide nothing more than a 'clinical' experience, and felt obligated on some level, then I would probably pass.
I agree with maninsoma. I don't feel that a 'happy ending' in anyway cheapens the masseur or the experience, as my preference more often than not is to simply enjoy a nice quality hour of massage.