Do you often get handwritten "thank you" notes from people? You probably do get a couple here and there from some especially grateful patients. How does it feel? To me it always feel special. A person bothered to find a nice card, to find some time, to hand write and to mail it. I still keep "thank you" cards from my former students and we don't throw away handwritten cards from patients.
My point is obvious. If you feel that a hand-written note is special, then others may feel this as well. Couple years ago a patient left our practice after he got a Medicare insurance. I sent him a note saying we would always be happy to see him again. After having a negative experience with that particular Medicare dentist, he came back to us. He showed my handwritten card that he kept. I took this as a lesson and write a personal note to every patient who for whatever reason leaves the practice.
In the same manner, we always send handwritten "thank you", sympathy and "get well" cards. And patients often mention and thank us for them.
It is just a little touch. It won't transform your practice overnight. But the cumulative effect of little touches can make a significant difference overtime.