I really do not believe it is a client's problem to worry about whether there are other people out there "more deserving" of paying for a provider's time or more in need of it or whatever. I do not view a therapist as "squeezing me in" - the woman has an appointment or she does not it. If she says she does, then I am as deserving as anyone else of buying that from her.
I also don't think of them as all that super special to think they are doing me a favor by allowing me to come to an appointment.