I like this idea. I am glad you thought of it. Some of my reasons to list.

I don't want my daughter asking about boo boos on my body.

I want to become a therapist to help others who SI and I can't preach what I dont do myself.

I am a wonderful caring individual who deservers respect from others as well as myself. (Not sure I typed what I mean)

My husband loves me and he deserves to not have to constantly worry about me.

Have not SI in sooo long and want to keep up the work
I know if I SI just once it will bring back the old feelings and addictions and I will start up again.

For me why SI if I know it is only a temporary fix to my emotional problems and I will see the SI later and feel more bad feelings for doing it. I could do something fun like paint.