I am not going to join my school play and choir this year, but how do I tell my director?

This school-year, I won't be joining the drama club and choir. But, my director(s), are going to push me to continue doing it, when I don't want to. I feel like my directors don't really deserve what I have to offer, and more. I got small roles (and yeah yeah I know...you fall down get up again...keep trying for a bigger role blah blah blah but....) but....my directors choose people out of faoritism...it's difficult to descrie how unfair my school is if you don't go there....also, the directors are harsh..and mean, and discouraging almost. I will not have myself be around this negative energy. For, I do not like them anymore. Also, I won't be joining the chorus...with the same director. I felt value-less. Zero. Nothing. Useless in her drama-club/choir. I want to know how to tell my directors I won't be coming back into the program....truthfully....I want them to know why...but in a nicer-way. Any ideas? AND PLEASEEEEEE PUT SOME CARING THOUGHT INTO THIS. Please<3

This is very important to me and I need advice.

Thank you so much for your time<3

THANK YOU<3<3<3