Insightful point floridarob; it is sad to read stories such as this.
I do also agree with Tarte that tips, presents, etc. make the sex way better, I see it as is a very cheap way of upgrading to business class, if you'll excuse the flight metaphor. I only realised this recently; up until last year, I would never tip as going rate here in London is quite high anyway, but since I started tipping (around 10%), I have consistently found my hires to be more 'enthusiastic'; one now french kisses deeply whereas he would have never done this before...