I've seen a number of reviews where reviewer stated that the lady had an off day and told the hobbyist, "I'll make it up to you next time."
Ladies, seriously... you in a service industry. If any civilian in a service industry makes a mistake, or does not satisfy the needs of their client, they fix the problem, and they pretty much do it for free.
If you value repeat business, because isn't it easier and less risky to have a repeat client whose safety factor is known, then get a clue...
If you already know that you screwed up, and care at all about retaining the hobbyist as a repeat client, then don't just tell him, "I'll make it up to you next time." If you say that, most of the time, you'll never hear from him again because why would he want to spend his time and money to roll the dice with the same disappointment again when there are so many other providers from which to choose?
Instead tell him, "Look, I know that I'm having a off day. I really do normally provide a more enjoyable time than we just shared. I would appreciate it if sometime in the next month if you can find the time to come back and see me again so I can show you just how enjoyable that time we share together can be. I will be happy to spend that time with you with no fee involved at all."
Also, if a lady blows an appointment after letting the hobbyist first drive to the vicinity of her incall location, she should still offer to spend some fee-less quality time just out of gratitude for his understanding... and the extra chance.
Everyone has a bad day, and things don't always go well as a result. How a provider frames that event at the end will determine greatly how the client responds... and what he is inclined to tell others about her.
Just something for a lady to think about while she sits alone waiting for the phone to ring again.