It's always a gamble. Think about it. You see many girls every day, but only some of them attract you, and if you met those girls, only some of them would still seem attractive to you after a while. We look at pictures and read reviews before we choose the girl, but they get no say in the matter (well, not the first time, anyway),
I think the girls deserve lots of credit here. Think about what it's like to always be "on", no matter what your gut reaction to someone is, and the difficulty of turning on the charm the moment you engage with a total stranger. It's got to be really hard. And everyone has off days.
Personally, I think the best way to manage the odds is to read reviews, and to do your part. Make sure you are clean, look your best, are polite, and that you treat her very well. Most people respond well to respect and kindness. There is a sticky post here (http://forum.tokyoadultguide.com/escort-service-reviews/4258-standard-practices-meeting-ladies.html) that has some very good suggestions.