Moreso the feeling of being promised something so great and then having that taken from me, especially since I've been patiently working, saving for this one trip.
You need to lose that mindset - you’re not being promised anything, other than the
potential for a good session.
Nothing is being taken from you, and more importantly you are not entitled to
anything.
Remember that you’re engaging with a human being, not a semen extraction machine. Between two human beings, there is no guarantee of a positive interaction. The financial incentive makes it more likely, but guarantees nothing. You also need to put in some effort - be well groomed, recently bathed, trim your finger and toenails, and be both polite and nice to the provider.
Even then, remember that a consummate (and adorable) professional like Manami has had a couple of less than stellar reviews. People don't always click, and that's just the way the world works.
You can hedge your bets by booking shorter sessions for your first time with a provider, and if it works out, you can book longer ones later. If it doesn’t work out, you’ve saved some of your budget to try again with someone else.
Most importantly, try not to have elevated expectations or feelings of entitlement.
There are no guarantees in this pastime. Even longtime hobbyists will have dud sessions, and also sessions where we have the lowest of expectations that turn out to be amazing.